mineral

Quartz (Milky and Smoky variety)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: White, tans, translucent to opaque; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 (Mohs scale)
Color: White, tans, translucent to opaque
Luster: Vitreous to waxy

Identified April 19, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: White, tans, translucent to opaque; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Formed through the cooling of silica-rich magma or from hydrothermal veins. This specific specimen appears to be a water-worn river pebble, shaped by erosion over thousands of years.

Uses & applications

Used in the manufacture of glass, ceramics, and abrasives. In this tumbled form, it is common for decorative garden stones, inexpensive jewelry (cabochons), or beginner rock collections.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz gets its white color from tiny pocket inclusions of gas or liquid trapped during crystal growth.

Field identification & locations

Identify in the field by its inability to be scratched by a steel knife and its lack of cleavage planes. Found globally in almost all geological environments, particularly in riverbeds and beaches.

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Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

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metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral