Quartz (specifically Milky/Gray Quartz)

Physical Properties

Hardness: 7 on Mohs scale; Color: Grayish-white, translucent; Luster: Vitreous (glassy) to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & Geological History

Formed from the cooling of silica-rich magma or from hydrothermal veins. It is one of the most abundant minerals in the Earth's crust and can be found in rocks from virtually every geological age, often forming in igneous pegmatites or metamorphic environments.

Uses & Applications

Used in glassmaking, electronics (piezoelectric properties), abrasives, and as a component in concrete. In jewelry, it is often tumbled or cut into cabochons; however, common specimens like this are primarily for amateur collecting.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. Ancient Greeks named it 'krustallos' meaning ice, as they believed it was permanently frozen water that would never melt.

Field Identification & Locations

Identify in the field by its hardness (it can scratch steel and glass) and its lack of cleavage (it breaks in irregular, shell-like curves). It is commonly found in riverbeds, mountain scree, and as veins in larger rock outcroppings.

Identified on: 4/17/2026

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