Quartz

“Terminated usually by a combination of a positive and negative rhombohedron, which often are so equally developed as to give the effect of a hexagonal pyramid. Sometimes one rhombohedron predominates or occurs alone.” — Ford, 1912

Keywords

geology, geometry, mineral, negative, positive, rhombohedron, crysal

Galleries

Crystals

Source

William E. Ford Dana's Manual of Mineralogy (New York: John Wiley and Sons, Inc, 1912) 174

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