Huge Single Carborundum Crystal from Niagara Falls, NY. Iridescent. 6 cms x 5.5 cms. Beautiful. Man made from synthesizing graphite and silicon carbide.
The process consists of heating a mixture of clay and powdered coke (carbon) in an iron bowl. Acheson, in 1890, originally attempted to synthesize artificial diamond, but ended up creating blue crystals of silicon carbide, which he called carborundum.
When heated to 4150°C, the silicon is removed, leaving graphite. The process was patented by Acheson in 1896.After discovering this process, Acheson developed an efficient electric furnace based on resistive heating, the design of which is the basis of most silicon carbide manufacturing today.The first commercial plant using the Acheson process was built by Acheson in Niagara Falls, New York, where hydroelectric plants nearby could cheaply produce the necessary power for the energy intensive process.
Carborundum Crystals are a by-product of this process and they are absolutely gorgeous. While this plant is closed, workers and others collected some of these crystals.