mineral

Clear quartz crystal

Quartz (silicon dioxide, SiO₂), likely milky or included rock crystal

AI-generated identification · may be incorrect

Mohs hardness 7; colorless to translucent with a glassy luster, conchoidal fracture, and no cleavage. Trigonal crystal structure; specific gravity about 2.65.

Identified August 25, 2026More mineral →

Explore Clear quartz crystal in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Mohs hardness 7; colorless to translucent with a glassy luster, conchoidal fracture, and no cleavage. Trigonal crystal structure; specific gravity about 2.65.

Formation & geological history

Forms when silica-rich hydrothermal fluids or groundwater precipitate in cavities and fractures, commonly in igneous, metamorphic, and sedimentary settings. Quartz occurs from ancient Precambrian rocks to modern veins; the image alone cannot establish age.

Uses & applications

Used for glass, ceramics, abrasives, electronics, and optical instruments; clear, well-formed crystals are popular mineral specimens, though this example appears modestly collectible.

Geological facts

Quartz is one of Earth’s most abundant minerals and is piezoelectric, producing an electrical charge under pressure. The specimen appears naturally fractured or partially terminated rather than a polished gemstone.

Field identification & locations

Identify by its glassy appearance, hardness, lack of cleavage, and ability to scratch ordinary glass; a steel knife generally will not scratch it. Common localities include Brazil, Madagascar, Arkansas, the Alps, and quartz veins worldwide.