mineral

Quartz (Chert/Chunky Chalcedony)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: tan, grey, and cream; Luster: waxy to vitreous; Crystal Structure: Trigonal (often microcrystalline); Cleavage: none (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: tan, grey, and cream
Luster: waxy to vitreous

Identified May 4, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: tan, grey, and cream; Luster: waxy to vitreous; Crystal Structure: Trigonal (often microcrystalline); Cleavage: none (conchoidal fracture); Specific Gravity: 2.65.

Formation & geological history

Formed through the accumulation of silica-rich fluids in volcanic or sedimentary cavities/veins. Often found in hydrothermal veins or as nodules in limestone/chalk.

Uses & applications

Used for lapidary work, decorative landscaping, and historically for making tools or starting fires (flint). Higher grades are used in manufacturing glass and electronics.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. It is piezoelectric, meaning it generates an electric charge in response to applied mechanical stress.

Field identification & locations

Identify in the field by its hardness (will scratch glass), waxy surface texture, and lack of visible crystalline faces in this macrocrystalline form. Frequently found in riverbeds and eroded mountain areas.

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