My father was a teacher of material science in a professional school, teaching young people learning some metalworking profession. So as a child, I learnt already something about heat treatment of steel, about “Austenite” and “Martensite”, the “lattice face centered crystal system” and other stuff you can nowadays look up in the internet if you really want to know what that is.
In my childhood and youth, I was used to seeing models of metal crystal lattice structures (made by my father from little plastic pearls representing atoms) as well as photographs of iron or copper crystals viewed through a microscope, and similar things.
One time, I think I was maybe 13 or 14 years old, my father had bought a bar of bismuth, (in case you don’t know, that is a heavy metallic chemical element, number 83 in the periodic table) and we spend one summer afternoon making bismuth crystals (like the one shown on the picture above). He had brought a Bunsen burner. In the house, there was an old kitchen (unused at the time) that was suitable for the purpose, having a gas tap where the Bunsen burner could be connected and a marble table. My father had brought a melting crucible with a tripod and a pair of crucible tongs.
He put the melting pot on the tripod and lit the Bunsen burner. A blue flame emerged. He put it under the crucible and put some pieces of the bismuth inside and then we waited for the metal to melt. Bismuth melts at 271.4 ° C, no problem for a Bunsen burner, so we did not have to wait too long and the pot was filled with liquid metal with a slightly yellowish color, a little bit like gold, a little bit like silver.
Then the Bunsen burner was extinguished. With a piece of card board my father removed some oxides and impurities from the surface. Then we waited for the liquid to cool. Soon, we could see patches of something like a crust on top of the liquid.
Bismuth, my father explained to me, is one of very few materials for which the solid form is less dense than the molten form. The familiar example for this is water ice. Ice swims on top of the water, while in most materials, the solid form would sink. But in the case of Bismuth, it floats.
After some time, before the crust covered the surface completely, he took the tongs, used it to grab one of the pieces floating in the melt, took it out and turned it around quickly. Now I could see that the solid Bismuth had grown down into the cooling liquid and had formed a beautiful crystal with a step-like structure that is typical for this material, in some places forming little spiral -like structures or structures looking like small amphitheaters. We tried it again and I also took out a little piece. He said that in order to get larger ones you had to wait for longer, but if you waited too long the crystal growing down into the melt would attach to those that were growing from the walls of the vessel at the same time. The ones we got measured between about one and three centimeters, but he later showed me a larger one. When the crystals cooled, the surface oxidized in the air. The thin layer of metal oxide is shimmering in colors resembling those of soap bubbles or spilled oil films. Each of the crystals was unique and different and all where very beautiful.
My father had also brought a gas bottle filled with nitrogen gas, with a rubber hose attached to it. He opened the tap of that bottle and nitrogen gas started streaming out. He took another crystal out of the melt and put it into the nitrogen stream while it was cooling. Since the crystal was deprived of oxygen this way, it did not form the colorful oxide layer. It retained a gold-like color.
Years later, on a visit to a trade fair where minerals, crystals, fossils and the like where sold, I saw such crystals for sale. They wanted horrendous prices for one, more than ten times the actual costs, and claimed that growing one took several days in a special furnace, in a complicated process. I knew better, it had been as easy as cooking a soup and had taken us maybe an hour or two.
My early exposure to metal and mineral crystals, microscopic images of them and similar things is probably one of the things that primed my interest for abstract art. Witnessing how these crystals were made was really a unique experience. The emergence of such beautiful objects – with a complex, unforeseeable and uncontrollable structure, all of them similar and each of them unique – from a hot, shimmering liquid is a magical moment. It is something special, at the border between science and art. These experiences are among the most valuable things I inherited from my father.