mineral

Quartz (Chalcedony/Agate)

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale; Color: translucent white to pale yellow/grey; Luster: waxy to vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: none (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: translucent white to pale yellow/grey
Luster: waxy to vitreous

Identified July 14, 2026More mineral →

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Physical properties

Formation & geological history

Formed by the deposition of silica from groundwater in cavities of igneous and sedimentary rocks over millions of years.

Uses & applications

Used for lapidary work, jewelry (beads and cabochons), and as a collector's specimen.

Geological facts

This specimen appears to be a water-worn or tumbled piece of chalcedony, a cryptocrystalline variety of quartz. It is one of the most common minerals in the Earth's crust.

Field identification & locations

Identify by its hardness (will scratch glass), waxy luster when tumbled, and lack of visible crystal faces. Commonly found in riverbeds and gravel pits.