BISMUTH CRYSTALS SCULPTURE :
BISMUTH CRYSTALS SCULPTURE, Coming from Japan, Madiel explain that it's really difficult to make beautiful piece. She is the only one to do that, and we are the first online retail store offering this Art Crystal. The crystals have a complex and fascinating geometric hopper form and are rainbow-colored from the oxide layer that quickly forms on them. The crystals need to be handled with care. Softly with both hands. Fragility item.
This is Madiel, and his workshop "Lange de feu" in Japan.
♦ FABRICATION PROCESS :
Basically the price depends on the weight. Secondary, the price depends on how difficult to make the same type of beautiful crystals.
Bismuth has a rhombohedral crystal structure, so it will form angular crystals.
Bismuth crystals in the deep pot are heated by the electric stove and are melted at 271.5ºC. Then, the melt (liquid metal) is heated up to 300 ºC in order to ensure that there are no crystals in the melt.
It takes 2 hours and half from room temperature. Then, the electric stove is turned off. Slowly, the melt starts to cool down. When the temperature decreases below the melting point, the crystal doesn’t appear immediately. This is supercooled condition of the melt.
Then, a crystal appears on the surface of the melt. The crystal grows both laterally on the surface of melt and downward into the melt. The crystal becomes bigger and bigger.
The crystal in the melt is invisible. So I push softly the crystal with tongs downward a little in order to check the timing of lifting it up from the melt.
Finally when the tip of the crystal reaches the bottom of the deep pot, I can know by pushing it with tongs.
Now it’s time to lift it up from the melt to obtain a large crystal without deep pot inner wall shape. It takes 30 min or 40 min after the stove is turned off.
While the crystal temperature is high in the air, the surface of bismuth crystal oxidizes. The crystal surface is covered by oxide layer.
The variations in the oxide layer thickness causes different wavelengths of light to interfere upon reflection. Thus it displays a rainbow colors. The mechanism is the same as the rainbow colors of soap bubbles.
The spiral, stair-stepped pattern of bismuth crystals is caused by a higher growth rate around the outside edges than on the inside edges.
Caution: Making bismuth crystals is dangerous because the temperature of liquid bismuth is higher than 272 ℃.
It forms those elaborate hopper crystals because the edges of the crystal structure are more energetically favorable positions than the interior and faces. That makes the molecules continue to form crystal edges but never fill in the centers when crystallizing out of solution.