Quartz – Natural, Rough, Colorless

Terminations are flat surfaces or faces at the ends of crystals. Crystals with terminations on just one end are called singly terminated. The other end is either attached to a matrix or lacks faces. Crystals with terminations at both ends, like those shown here, are called doubly terminated. Set of 7 "Herkimer diamonds" (quartz). Herkimer Co., New York, USA. © Rob Lavinsky, www.iRocks.com. Used with permission.

Article: Gem Formation: How are Gemstones Created?

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