mineral

Quartz (Gravel Fragment)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Semi-translucent brownish-gray; Luster: Vitreous to dull; Crystal structure: Hexagonal/Trigonal system; Cleavage: None (conchoidal fracture).

Hardness: 7 on Mohs scale
Color: Semi-translucent brownish-gray
Luster: Vitreous to dull

Identified July 13, 2026More mineral →

Explore Quartz (Gravel Fragment) in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Hardness: 7 on Mohs scale; Color: Semi-translucent brownish-gray; Luster: Vitreous to dull; Crystal structure: Hexagonal/Trigonal system; Cleavage: None (conchoidal fracture).

Formation & geological history

Formed through the cooling of magma or by precipitation from hydrothermal veins. This specific fragment appears to be a worn piece of alluvium, likely millions of years old, weathered from a parent rock.

Uses & applications

In this small, raw form, it is primarily used for industrial purposes like aggregate in concrete or gravel for landscaping. In purer forms, used in electronics and glass manufacturing.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. It is chemically and physically resistant to weathering, which is why it often remains as small pebbles after other minerals have eroded.

Field identification & locations

Identify by its ability to scratch glass and lack of cleavage. Common in riverbeds, soil, and outcrops globally. Collectors typically look for larger or more colorful varieties.