Copper Silicate Showing Rhombohedral Tetartohedrism In the Hexagonal System
This is a crystal of Copper Silicate (Dioptase) with a rhombohedron of the third order, (s), in combination with the prism of the second order, (m), and the negative rhombohedron, (r). This crystal is an example of rhombohedral tetartohedrism in the hexagonal system.
Keywordscrystal, prism, copper, crystallography, rhombohedron, silicate, dioptase, negative rhombohedron
George Huntington Williams, Ph.D. Elements of Crystallography for Students of Chemistry, Physics, and Mineralogy (New York, NY: Henry Holt and Company, 1892)