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  • The Ethics of Doing

Obsessidian: A Material Study of Volcanic Rocks

The study was conducted as part of a final project in the Department of Industrial Design at Bezalel, under the supervision of Prof. Hanan de Langa, and with the assistance of the Department of Ceramics and Glass Design and the Department of Jewelry and Fashion, 2016-2018

My personal love for natural materials, volcanic rocks and fascinating natural phenomena, combined with the desire to learn and discover through my own hands, led me to dedicate my final project in industrial design, supervised by Hanan de Langa, to a material study of lava and volcanic rocks. In this study I examined the energy and material transitions between lava and volcanic rock: what are the factors influencing the formation of various rocks, can the natural process and the products obtained from it be manipulated, and can the lava and by-products of volcanic eruptions be used as raw material?

“Obsessidian” is a research project that was born out of a personal love of nature and rocks, and evolved to join my other passions in the area of matter. The meaning of “Obsessidian” – the portmanteau of “obsidian” (volcanic glass) and “obsession” – describes me well in the process.

As a designer and researcher, it was important to me to be involved in the process itself as much as possible: to feel the material in my hands, to work with it closely, to know how it feels to melt, pour, grind, and filter – all firsthand. I took advantage of the resources offered to me as a student at an institution that combines various fields of design and art, and I turned to other departments for help and enrichment of knowledge, so I could deal with the material in the best possible way: outside of the Industrial Design Department, where I was a student and which provided most of the study’s resources, a bit part of the study was conducted in the Departments of Ceramics and Glass Design and Jewelry and Fashion. I went through the process while conducting “obsessive” documentation and drawing, so that if I wanted to, I could go back to the discoveries of that study even years later.

“Obsessidian” is not just a finite object: it is a process. A comprehensive and experimental study of four volcanic rocks: basalt, red scoria, black scoria and pumice. The process was done in a continuous, systematic, and controlled manner, in which I tested the material in a wide and comprehensive context by means of four different research tracks: machining, metal, glass and ceramics.

The raw material proved to be an elusive material moving in its various states of aggregation between glass, metal and stone – so I had to decipher it while working, create unique techniques for processing it, and understand when I could force my will on it and when I should allow it to behave as it pleased.

1. Research Background

A. Iceland – The Starting Point

During my third year at Bezalel, I was lucky enough to go on a student exchange in a magical and distant country – Iceland. I have always dreamed of traveling in Iceland, but when I got there, what I saw surpassed all imagination, and the landscapes I encountered were different from anything I had known before.

Iceland is situated on a “young” island – about 23 million years old. As such, the island is geologically active, and it has countless fascinating geological phenomena: geysers, volcanoes, hot springs, calderas and more. What caught my attention in particular were the rock formations that I found: myriad colors, textures, and various crystallizations (Figures 1-8). The subject fascinated me, and so I began collecting stones, and then tag, locate, and try to learn more about the different types and how they became what they are. The turning point was my discovery that rock could be melted – that is, returned to a liquid state (lava), and that its solidification under normal outdoor conditions would usually result in the formation of volcanic glass (obsidian). It was this realization – that I had the power to intervene in the energy cycle of the rock, between the magma-eruption and the final rock – that motivated me towards the significant study that I elaborate here.

Figures 1-8: Volcanic formations in Iceland

B. Geological Background

Brief Explanation of Volcanic Areas:

Volcanism is a collection of processes that result in the formation of plutonic and volcanic bedrock. The primary volcanic process is the formation of magma in the depths of the earth as a result of rock melting through rising temperature, pressure release and flux melting (melting in the presence of liquids). The molten rock accumulates in magma cells, where it solidifies into plutonic rock, penetrates the surrounding rocks as plutonic intrusions or is transported to the surface by feed pipes. The magma erupts from the feed pipes in the form of a lava and creates volcanic rocks, which amass to volcanic points or extensive basalt surfaces that extend to long distances.

Volcanism is not a universal phenomenon but is limited to certain areas of the Earth: along boundaries between tectonic plates, along faults (a fissure formed in the rocks of the Earth’s mantle as a result of pressures) and above intra-plate hotspots.

Illustration 1: The energy cycle of rock

Types of rocks and their formation:

The rocks formed as a result of volcanic eruptions are varied, and they differ in properties and in the texture – differences that affect their appearance. There are two main types of volcanic rock textures: volcanic and glassy. The volcanic texture has many formations, including visible crystals, a porous or extrusive (interconnected spaces) structure and so on. The glassy texture usually has a uniform and smooth structure, and a glossy appearance with partial transparency.

Illustration 2: Volcanic areas1

There are four main causes for the differences in volcanic texture:

* Cooling speed: How quickly does the emitted lava cool down?

* Viscosity of the solution: The viscosity of the material will affect the ability of crystals to form, and thus the rock’s structure.

* Pressure: Under what conditions is lava emitted – forced out with pressure or flowing?

* The substance concentration in the solution: What is the concentration of the substances that make up the rock?

Each of these conditions will affect the appearance of the rock and its properties, so that two different stones, with a similar composition but with a completely different appearance, can be observed. If we examine, for example, pumice and obsidian, we will notice that both are very similar in composition and are usually formed from a silica-rich lava (rhyolitic or dacitic lava). Both are formed by the rapid cooling of the lava, but they differ in appearance and texture due to the pressure of the lava emission – pumice is a lightweight and porous rock because the lava is emitted at such a pressure that gas bubbles get trapped inside it during the eruption; obsidian, on the other hand, is a smooth, glassy, ​​and shiny stone because it is formed from a rapidly-cooling flowing lava that does not allow crystals to develop during solidification. Thus, it can be said that pumice is foamed obsidian.

Illustration 3: Different rocks and their properties2

C. Archaeological and Historical Baggage of Obsidian and Volcanic Rocks

Volcanic rocks usually carry historical or archeological baggage. Throughout history, basalt has been widely used to make bowls, cups, mortars and pestles, basins and ritual objects. Humans were also able to build large sculptures, tombs and bricks from this material, probably because of the ability to process it and its “malleability” – somewhere between limestone and marble: not as difficult to process as marble, and not too soft as limestone.

Scoria and pumice are rocks whose use have been little documented throughout history, perhaps because they are too soft and not durable. Scoria was used to create figurines and small sculptures, and the most impressive find that is related to this is the 233,000-year-old figurine of a woman who was found in Birkat Ram in the Golan Heights, and is the world’s first example of an art object.

Figure 9: A figurine of a woman found in Birkat Ram, Israel Museum

Obsidian is a natural volcanic glass rock, formed by the rapid cooling of felsic lava (feldspar- and silica-rich lava). Obsidian is of great archaeological importance, since the rock – used in ancient times to decorate and create arrowheads, blades and scrapers – was widely traded as part of the Neolithic Revolution. The rock was highly esteemed in certain cultures of the Stone Age, because, like flint, it could be chiseled to form sharp blades and shaped into arrowheads. It may also have been polished to create ancient mirrors. By to the distribution of objects found throughout the Fertile Crescent, it turns out that obsidian was one of the first products regularly traded: whole lumps and products processed out of this material were carried on the back – before the domestication of animals for transport – from the Anatolian Plateau to Israel and the Persian Gulf as early as 8,000 BCE. The inhabitants of pre-Columbian Central America made extensive and sophisticated use of cut and processed obsidian, for tools and ornaments.

The common use of obsidian as a gemstone is made in jewelry, ornaments, and architecture. Although obsidian is rare in Australia, ornaments made from it have been found in Queensland. The rock had also been mined on the island of Melos, in the southern Aegean Sea, for 12,000 years by the Greeks and Romans – who used it as a gemstone, and also for producing mosaic stones inlaid on floors (this had also continued in the Byzantine period). The Mayans, and later the Aztecs, also mined it and used it as a trade coin and gemstone, to which they attributed magical properties.

Obsidian is used nowadays in heart surgery, as fine scalpels of this material are equipped with blades that are up to five times sharper than those of fine steel scalpels. Moreover, some tend to attribute medicinal properties and magical abilities to the stone – one example is the mention of it as “dragon glass” in the book series A Song of Ice and Fire (“Game of Thrones”) by George R. R. Martin, as a weapon against the “white walkers”.

This stone, which carries with it a diverse historical baggage and is shrouded in an aura of mystery and magic, seemed to me an interesting starting point and a well-worth study object for the final project, and I could not wait to begin examining it in depth.

Figure 10+11

2. Actions and Material Study

A. Selection of Raw Materials

Once I had decided to explore volcanic rocks, I had to decide on which rocks to focus. I knew that in order to study rocks properly, I would have to ones that are accessible to me, and because I was aiming for an empirical study, they would have to match the temperatures that my current working conditions allow.

After an initial search, I decided to focus on four types of rocks, three of which can be found in Israel (also the fourth – pumice – but only what drifts across the Mediterranean from Greece or Italy).

Below are the stones (scale: about 10-15 cm across):

Figure 12-15

* Basalt: formed by the rapid cooling of basaltic lava exposed on the Earth’s surface (usually in Hawaiian eruption: slow flow); it is of low viscosity and melts at around 1200 degrees.

* Black scoria and red scoria: lava that solidified while in the air, before the gas bubbles were extracted from it (usually in a Strombolian eruption – under pressure); it is of low viscosity and its melting temperature is around 1200 degrees. The color difference between the black and red scoria indicates differences in their structures and melting temperatures, and the processes associated with the oxidation of iron present in the lava.

* Pumice: Pyroclastic rock, formed by the rapid cooling of silica-rich lava that also and gas bubbles and water vapor. The porous rock is light enough to float on water, has a high viscosity and a melting temperature of around 900 degrees.

The process of selecting the rocks on which I focused included conversations with local geologists about their presence in Israel – I inquired about some areas that had been volcanically active and went to collect a store of raw materials.

The Golan Heights has many areas that were geologically active – dormant volcanoes such as Mount Bental and Mount Avital, Tel Saki, Tel Fares and more. Many areas serve today as quarries for what we call tuff: a stone that is in fact scoria. Basalt is also very common in the Golan Heights. This is how I found myself wandering in the Golan, between quarries, dormant volcanoes and various ponds. The sites where I collected the materials were Birkat Ram, Tel Fares, Mount Hermonit, and the around Mount Bental.

Figures 16-19: Collecting the material

B. Methods of Processing and Working Techniques

Since it was not clear from the beginning what the preferred technique and processing method for the material were, I divided the work into several “tracks”: metal, glass, ceramics, and machining. The “tracks” include different processing methods that are commonly used with the material they are named after, and occasionally experiments with mixing certain materials from the same category (for example, in the metal track, one of the techniques I used is “lost-wax” casting, in addition to other experiments of mixing stones with metals).

Figure 20: The powders of the various rocks after grinding them

The study led me to grind the material into powders, because that way it was easier to process, or simply because this was required by the technique by which I wanted to work the material. I made the grinding myself using a tromel – a ceramic vessel that contains ceramic balls of different sizes, which grinds materials using a rotary motion.

The Metal Track:

The main idea behind this track was that if the stones could be melted, maybe they could also be cast. In my search for references I did not find any project that involved casting of this material, so I felt that this direction had potential.. In this track, I tested casting into an open mold, casting using the “lost wax” method and mixing with various metals.

Casting Using the Lost-Wax Method:

After experimenting in several areas and discovering that the material was too viscous and intractable, I decided to proceed with lost-wax casting (in gypsum) in a centrifuge: the idea was that the centrifuge would apply enough force on the liquid material to push it into the negative spaces in the gypsum before it cools down.

In this test I noticed the following:

* All rocks can be cast except pumice. It has proven to be the most viscous material (probably due to its high silica content) that is intractable.

* There was still a problem of viscosity and fluidity. The butane gas I used reaches about 1200 degrees, so it was difficult to create a sufficiently liquid material for casting. Although the materials could be cast, they sometimes hardened at the object’s opening and did not fill the entire negative space.

* Fractures and pores: lots of air seems to penetrate the material during casting, causing the castings to become porous. This also created bubbles and weakened structurally some of the castings, which were broken when they were released from the mold.

* The conversion ratio between the various materials and the wax workpiece is unclear, which leads to create many blockages in the crucible, or insufficient material in the mold.

* The material reacts differently on contact with gypsum than when cooling in the air (visually).

The conclusions that followed were:

* I must lower the melting temperature as well as the viscosity of the material (this is directly related to my experiments with glass).

* The cast material is similar in properties to glass (obsidian) and, therefore, unlike in ordinary metal casting, it must be allowed to gradually anneal (as is customary in glass) before its removal from the gypsum (to prevent thermal shock).

* The conversion ratio for each material versus the wax should be determined separately.

* I noticed the aesthetic difference between areas exposed to gypsum and those that are not.


* I solved the viscosity problem through experiments with glass – adding a small amount of borax (about 5%-7%) proved to be effective in lowering both the viscosity and the melting point, and once the new material was formed (the mixture of the raw material with borax) it could be melted again without significant effort.

* I discovered the conversion ratios empirically, and they all ranged around 1:2 (material to wax).

* I realized that I could choose the places where the glass under the gypsum casing would be exposed – by areas prone to fracture in the workpiece, or by processing of the material surface.

* I also examined another possibility of casting by induction melting. The casting is done by pouring the liquid material into an open gypsum mold (and using vacuum to release the air), or into a compressed sand mold.

* Of the four substances, only basalt has proven to melt easily by the induction method, probably due to the high concentration of iron in it. In addition, I have examined various additives to basalt powder that may help in liquifying it for pouring. I found that the addition of a small percentage of copper oxide promotes melting, and even lends an interesting reddish tinge to the casting.

The insights from these trials were:

* Only basalt can be melted efficiently by the induction method.

* Casting by pouring introduces a lot of air into the material. This creates bubbles, which weaken the structure of the material and render it very fragile.

* Direct contact with sand creates a different (more metallic) aesthetic.

* It is very difficult to control the way the material is poured.

* Mixing the material with copper oxide creates varying tones during hardening.

* t is difficult to cast large objects – the material breaks more easily and is unable to spread into the entire mold.

Next, I tried to hone my skills in both centrifugal casting and induction melting so that I could anticipate the result of each casting. The most significant discovery in this area was the understanding that the cast objects induce an illusion of time – they look ancient from the moment they are “born”, as well as the realization that it is possible to produce ancient tools by new technology (arrowheads, figurines, etc.).

Figures 21-16: Experiments in the metal track

The Glass Track:

Delving into the glass track started with the thought that I might be able to produce volcanic glass that could be blown. This required a prior understanding of the most suitable raw material of the four for glass making, and determining the temperature required for the process. In this track, I tested blowing glass made from the stones or mixed with them, powder- or granule-coated glass, and creating glass from the stones as raw material for blowing.

Creating glass from the stones as a uniform raw material:

After several unsuccessful attempts at blowing the raw material, I tried to produce the glass without any external additive to the stone as follows: I tested, using ceramic furnaces, the crystallization forms of the different materials (after grinding) at different temperatures.

I was unable to produce anything close to volcanic glass, and a new requirement came up in other experiments to try and lower the materials’ melting temperature. Therefore, my next step was to take about ten melting agents and mix a small percentage of them with the various raw materials. I did this test for each raw material, and now I was also interested to see how the materials will affect the crystallization, texture, and color of the raw materials at different temperatures. Thus, I tested adding 10 different melting agents (and control group without an such agent) for each of the four raw materials, at four different temperatures: 950, 1050, 1150 and 1220 degrees. I conducted about 200 tests, and what I witnessed was that the different additives yield different, varied, and interesting formations, and uniquely affect each of the different raw materials. I made sure to document meticulously the properties of the new materials: color, crystallization, liquidity, powderiness, etc.

I was also able to produce volcanic glass: basalt mixed with lithium carbonate, sodium carbonate or borax created a material with the same appearance and similar properties as those of natural obsidian: black, shiny, and partially transparent glass. Using these combinations, I was able to start producing volcanic glass in a controlled manner.

Unfortunately, I have not yet been able to blow any of the glasses I have developed, but I have come to the following conclusions:

* Lowering the temperature: Some of the stones began to react at lower temperatures with various additions. For example, I later knew how to use the addition of borax when I was casting in a vanishing wax technique.

* Different crystallizations: the different additions and different temperatures yielded a wide range of aesthetic options that I could work with; New properties have also been discovered in some of the crystallizations, such as magnetism.

Figures 27-33: Experiments in the Glass Track


The Ceramics Track:

In this track, I studied how the various stones function as glazes, and how they react when mixed with different ceramic materials.

Function as glaze:

After several attempts to mix the raw materials with the ceramic materials, I decided to focus instead on creating a glaze. Initially, my experiments involved mixing the ground raw materials in a transparent glaze in varying percentages: these tests yielded unimpressive results.

The real discovery came when I tested the functioning of the raw materials themselves as glaze – mixing them with nothing but water. The red scoria, basalt and pumice did not provide a an aesthetically satisfactory result, but the black scoria proved to be a functional and stable glaze, with a very interesting aesthetic. Firing was done at a common glazing temperature, 1220 degrees, which is also the melting temperature of scoria.

Figures 34-37: Experiments in the glass track

Figures 34-37: Experiments in the glass track


Machining Track:

In this track I checked which of the stones I collected in the Golan would be the most convenient for small-scale machining, and which machining technique was preferred for this operation.

I turned to companies that process marble with CNC (Computer Numerical Control), where it became clear to me that existing machines are too coarse for processing the stones that I brought. Attempting to work on a smaller metal/wood CNC machine failed due to a mismatch of the milling head (diamond milling is required – a regular cutter will wear out), so I turned in a different direction: lathing.

First, I focused on scoria, as I felt it was a stone that was hitherto not used much for making tools, unlike, for example, basalt. Moreover, basalt is harder, denser, and heavier and therefore less convenient to process. The properties of scoria – the brittleness, the porosity, and the light weight – led me to choose it as the most convenient stone to process (pumice, as mentioned, was impossible to obtain in Israel).

Lathing the scoria required planning: how do I fix the stone to the machine? It is impossible to clamp it inside because it is so porous that it will surely break. The solution was drilling into the stone and using epoxy glue to fix a threaded rod inside. On this rod I then mounted another part, which was the one that was eventually clamped in the lathe, and I closed it with nuts. After finishing the work, I removed the bottom that was connected to the rod.

The lathing itself was done with a metal lathe because I had to operate slowly and carefully – any incorrect intrusion into the material could have broken it. The rotational speed was limited due to the material’s “softness”, which increased my wariness, but I finally concluded that the material can be processed relatively easily in a lathe, as long as I work slowly and patiently.

Figures 38-42: Experiments in the machining track

Figures 38-42: Experiments in the machining track

C. Summary and Conclusions

All the processes I have outlined here were carried on in parallel, allowing me to learn from each of them and cross-examine conclusions and discoveries with each of the other areas.

Most of my tests and experiments required a long and consistent process, because I dealt with different tracks like ceramics, glass and metal, whose results were not immediate, and the tests necessitated many preparations and steps.

Eventually I compiled the different conclusions and discoveries I had reached in a list, and once I had this list, I was able to decide what I wanted to focus on, and what I wanted to do with those discoveries.

My main conclusions and discoveries:

* Different crystallizations are possible according to the composition of heat and material, as well as the formation of different effects of colors and textures.

* Lowering the melting temperature is possible using several different melting agents, but it affects the material chemically, and to some extent changes it.

* Reducing viscosity is possible by means of several different melting agents.

* The material can be combined with various ceramic materials.

* Black scoria functions as a stable glaze on its own with no other additives.

* In the lost-wax method of casting, the material is brittle and fragile, probably because of the ingress of air into the material in its rapid melting process (something that does not occur, for example, in the glazing process).

* The red scoria and black scoria can be easily machined on a small scale, and lathing is a possible technique for machining them.

* In a certain composition it is possible to melt parts of the stone and leave other parts exposed – thus deciding which parts will be impermeable and which parts will be absorbent.

* All materials can be cast except pumice.

* In the lost-wax method of casting into a gypsum mold, the resulting aesthetic appearance is of an object that speaks time, with an archeological quality.

* In cast items, there is a visual difference between the object’s interior (shiny and glassy) and its outer surface that contacts the gypsum.

In my opinion, focusing only on one direction would not have done justice to the extensive research I conducted, so I ultimately decided to rely on a limited number of discoveries for creating the final objects.

Now comes the formal search phase – creating new objects following the material study.

Figures 43-46: Photographed pages from the research notebook

3. Development of New Objects; Implementation of the Conclusions and Discoveries from the Practical Study

A. Search of Form and Connection to Archeology

The connection of the raw materials I have chosen – volcanic rocks – to the shapes of archeological finds is a natural connection, due to the archaeological and historical baggage that they carry and which I have detailed above. A closer examination of the materials made me turn to the past, to the tools that were once made of those materials. I found the connection to archeology to be a significant one, and moved on to examine ancient objects as a source of inspiration for forms. A short online search in the collection of the Israel Museum made me realize that I must visit there and see things up close.

The Archeology Department of the Israel Museum is a large and interesting department, divided into periods and cultures. I decided to take time to wander around the department and take a closer look. I learned about the vast stone culture that existed here – mortars and pestles, the obsidian path, and of course the fertility figurine that is the oldest art object ever found.

As the project progressed, I was inspired by the shapes and objects I saw: figurines, hunting tools, and especially receptacles, whose main charm in my eyes was their simplicity. These are vessels whose essence was function, and were therefore processed only in the usable parts, as opposed to bowls and incense vessels decorated with various ornaments. I was also interested in the culture of glass that existed here – the ancients called glass “stone of the flowing kind” – a designation that matched the spirit of my casting work. I sketched shapes and objects out of deep observation and decided that although my objects would be made with a new stone processing technique – they would remain attached to the historical baggage that accompanies them.

Figures 47-52: From the visit at the Israel Museum, the Archeology Department

B. Manufacture of Three Tool Series

I decided to create three series of tools that embody three major discoveries of the study.

The inspiration for the tools’ forms originated, as mentioned, in local archeological finds: simple, often functional, form of receptacles.

Each series stands as a family in its own right, and yet the various items can be combined, and the aesthetic connection between them will still be clear.

Figure 53- An item from each family

I have derived the names of the families from three volcanoes that I had visited since I became very interested in the subject, in the depths of Iceland. The Saki family is named after Tel Saki in the Golan, the Fuego family is named after the Fuego volcano in Guatemala, and the Askja family is named after the eponymous volcano in Iceland. Each of the families represents one major discovery, which I distilled and refined until I was able to sustain it in the respective series of tools. Each discovery and set that followed it introduced new challenges, new problems that needed to be solved, as well as further interesting discoveries.

The Saki Family:

First Discovery: 100% Stone Glazing

משפחת סאקי היא משפחת כלים העשויים מפורצלן, ומזוגגים בזיגוג העשוי 100% סקוריה שחורה.

The Saki family is a family of vessels made of porcelain, glazed with 100% black scoria.

The discovery of black scoria as a glaze with interesting aesthetic potential in itself was rather unprecedented. Now, I had to decide what would be the material that would blend optimally with this glaze. It was clear to me that a material that can withstand a high temperature (1220 degrees) was needed, and that limited the possibilities.

On top of that, I knew the tools I would like to make would most likely be by casting, as I also wanted to create a variable appearance for identical vessels and keep the glaze at the focus.

I now attempted to reach the most appropriate aesthetic combination for this glaze. I eventually chose porcelain; I did not want to intervene with the vessel other than using these two materials (i.e., to not add any more glaze, for example), and the porcelain itself is waterproof following high firing without any additional coating.

The whiteness of the porcelain was an interesting contrast to the dark color of the glaze, and its slightly glassy appearance connected visually and conceptually to the raw materials – stone-coated earth.

Now there were new challenges:

* Porcelain is not a simple material to work with. It contracts greatly and tends to warp depending on its wall thickness. In addition, the glazing affected the distortions – variable stretches of the material inside and out due to differences in the contraction and expansion of the materials created interesting visual appearances.

* Finally, I decided to make vessels whose shape is directly affected by the glazing – the slight distortions created in the kiln emphasize the glaze, and also lend a certain degree of randomness to the appearance of the finished vessel.

* Another issue was the dipping: when the vessels were dipped for too long, the material’s contraction was severe and sometimes caused fractures and cracks.

* Moreover, under certain conditions the material would leak in the kiln – another aspect of randomness. I had partial control over that, in the way I positioned the vessels before firing.

* While working I discovered that when the glaze is spread over a large surface area, it gets an interesting rusty-metallic look. In addition, different degrees of absorption resulted in different appearances, which could not have been anticipated before the fire.

The vessels I chose to produce were a set of kettles and cups of tea, various plates and saucers, and even small jugs – all inspired by archeological utensils. Each tool is “one of a kind”, even though they all came out of the same mold. The final move is the glazing, and the way it spreads over the vessel – a component over which there is only limited control.

Figures 54-56: The Saki family


The Fuego Family:

Second Discovery: Lava Castings

The Fuego family, the cast family, evolved from the castings I made while working on the metal track. The main discovery from this family is that some of the volcanic rocks can be cast when they are in the form of lava.

The idea behind Fuego is new tools that are “born” with an antique look. I harnessed the archeological appearance of the tools to creating a few small vessels, made of volcanic glass, which look like vessels that could have been found in an archeological dig.

When I approached the creation of this family, I faced new problems: the viscosity of the material, and processing the material – is it glass or metal?

* To solve the problem of material viscosity I used my discoveries from the work with glass and added a small percentage of borax. I also discovered that each of the raw materials (except pumice, which I was unable to cast) has a slightly different appearance and properties after casting.

* I left a few of the cast objects broken; this is how the inner shiny part, the volcanic glass, got exposed to the viewer. The exterior, the part that comes in contact with the gypsum, looks antique. I also tried to do some external processing of the objects’ surfaces: manual sanding, sandblasting, and an attempt at surface melting.

* I found that the larger the vessel, and the thinner its walls, the harder it will be for the material to flow and reach the whole mold. This property brought about a cooling of the material while still liquid, and in fact left a bright border wherever it did not reach the end of the negative space.

* The series of objects included receptacles, but usually those that could no longer contain liquids. The thinking here was of an archeological series, and as such, only partly functional.

Another move I made stemmed from the thought that I now had in my hands a new tool that the prehistoric man did not have: casting in a centrifuge. The tools available to prehistoric man for processing stones included engraving, breaking and missing – and I now had the ability to cast those objects more accurately and easily. This led me to attempts to cast arrowheads, idol sculptures and figurines, scarabs and more. The same material, the same object – a new technique: ancient tools produced industrially.

This thought gave rise to a new direction: the “new idols” – new objects that look ancient.

I realized that I could use this ancient and magical material to create modern objects: items that could not really be found in archeological excavations. The thought of a unicorn I found in a Kinder egg, made of obsidian, and looking as if it were discovered in excavations and created about 5000 years ago, seemed exciting to me, so I cast disposable cups and toys out of Kinder eggs as a miniseries of new idols.

Figures 57-61: The Fuego family


The Askja family:

Third Discovery: One Object, One Substance, Two Different States

The Askja family is the that of the natural objects, and it is about the connection between two different states of the same substance. The material at the center of this family is the scoria stone, which I machined (lathed).

The idea behind this family was of vessels in which the original raw material is still present and exposed, unlike the previous two families. Scoria has both aesthetic and functional strength as it is: porous and with liquid absorption properties; it is also suitable for insulation and surprisingly lightweight.

The goal now was to produce vessels that are part impermeable and part porous. I knew I could melt the material directly using a burner, but in this technique my control was limited. This problem brought me back to my experiments with glass: I went back to testing with the melting agent additives, to find an additive without which the material will not melt at the same temperature.

I found quite a few additives that gave me the desired result. Now I had to check the reaction of stones, and the resulting appearance at different temperatures. I ran several tests with scoria coated by each of the different materials that were expected to react. I checked different temperatures, until I found the material that gave me the most interesting visual result. Also, I had to find the exact temperature at which the vessel made of pure scoria is unaffected, or slightly affected, whereas the coating (also made of scoria, combined with a small amount of melting agent) does melt.

When I found the exact material and the particular temperature (following hundreds of tests), I was ready. I could now seal certain areas of the vessels and leave other areas exposed, with almost full control. Here, too, quite a few problems arose during the work: the reaction of the materials varied according to the amount of coating I applied, and the vessels reacted differently in different kilns. Nevertheless, I retained most of the control, while occasionally unintended results also appeared, which I welcomed.

Figures 62-65: The Askja family

4. Summary

A. Summary

be clear discoveries. Moreover – the references to working with lava or similar materials were meager, but this mystery of the material and its uncommon use attracted me to follow this path that had hardly been explored.

Throughout the process I had to understand the material and face new challenges and problems that arose at each stage of my progress. But in the end, the consistent and systematic work bore fruit: many different discoveries, the development of working methods and the processing of the material were realized in three families of objects, which differ in their appearance and in the way the nature of the studied material is expressed.

This study has led to a breakthrough in a field that has not been sufficiently explored: lava as a raw material. The discoveries, working methods, and new materials I have developed during the project have enormous potential for other fascinating and interesting developments in this field and in related fields.

B. Further Projects

My study led to quite a few crossroads and ramifications that I chose or did not choose to follow. Some of the revelations developed into the families I created, and others were abandoned along the way, thinking I might return to them later.

Two of these discoveries evolved to other rock projects, subsequent to the study:


יציקות הלבה (משפחת פואגו) התפתחו בהמשך לפרויקט נוסף בפני עצמו, שנקרא “Neo-Archeology”.

The lava casts (the Fuego family) evolved into another separate project, called “Neo-Archeology”. This is a conceptual project, which seeks to examine the current culture through a filter of archeological objects that tell the story of cultures and customs. The project asks the questions: What evidence would human culture leave behind today, if it existed in prehistoric times? What are the idols and figurines we would immortalize? What tools and objects would we leave behind?

Using the processing technique I developed in the current study, I was able to transmute plastic objects and artifacts familiar to us from everyday life into archeological finds. The “neo-archeological” objects present us with a conflict: a disposable knife made of stone, or a credit card made of obsidian; items we would expect to find at an archeological site, but also close to home.

Figures 66-68

“Obsessidian 2.0” 

Obsessidian 2.0 is a project created for the Tel Aviv Biennale of Crafts & Design at the Eretz Israel Museum, and it continues and expands the “Askja family” to new processing technologies.

This project connects the oldest material in the world (lava and volcanic rocks) with the current technology of machining using a robotic arm (CNC) and creates a singular visual show that cannot exist in nature – the stone next to the glass, the source next to the product.

Figures 69-71

Appendix – Additional Experiments in the Study Process

A. The Metal Track

Mixing with different metals:

Combining the stones with different metals yielded an interesting visual result, but at this point I decided to focus on the mixtures in which the lava and the stones would form the main mass of the material.

Open Mold Casting:

In the preliminary tests, I tried to melt the materials in the crucible and pour them into an open mold. I realized that the materials are so viscous, and their melting temperature so high (compared to metal and glass, for example), that it is almost impossible to “pour” them after melting, and they harden almost immediately.

Other experiments in the field of metal were the combination of metals with the stones – filling the porous material with brass, casting on stones, as well as experiments in combining them by melting. The results of these tests were interesting, but I felt that the real potential lay in casting of the material itself, and not in adding anything to it.

B. The Glass Track

Blowing Glass Made of or Combined with Stones:

The first experiment involved melting black scoria in a glass crucible, then attempting to blow it. The scoria melted but was highly viscous and could not be blown. I then tried mixing the stone with about 50% glass: this too failed, as the glass did not mix properly during melting and could not be blown, and I surmised that such a large addition of external material decreases the use value of the raw material.

Blowing Glass Coated with Stones or Stone Powder:

I also did other experiments in which the blowing itself was of plain glass that we rolled beforehand on scoria grains or powder. The results were very interesting visually and texturally, but again – the main material was the glass and not the stones.

A. The Ceramic Track

Mixing Stones and Stone Powders with Ceramic Materials:

The use of volcanic rocks is not new in the ceramics industry: there are additives such as basalt granules and pumice powder, for example, which can be admixed into glazes. Moreover, there are quite a few references to mixing basalt with the material itself, so after a few attempts in this area I decided to give up this path and focus on glazes instead.


Volk, Shula, The Technology of Ceramics: Material for Thought, S. Volk Publishing, 2013

Drach, Ami and Genshrua, Dov, Field Trip: Designing Contemporary Prehistoric Tools, Tel Aviv: Amidov Studio, 2017

Emmons, William H., Thiel, George A., Stauffer, Clinton R. and Allison, Ira S., Geology: Principles and Processes, McGraw Hill, 1955

Wyckoff, Jerome, Rock, Time and Landforms, Harper & Row, 1966

Encyclopedia Britannica

Energy muse (inspirational crystal jewelry):




Other sources:

The Israel Museum – Department of Archeology

Geological Icelandic House – Volcano

Shmuel Meiri – geologist

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