mineral

Quartz (Bull Quartz)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to translucent tan/brown due to iron staining; Luster: Vitreous to greasy; Crystal Structure: Trigonal (often massive in these specimens); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Milky white to translucent tan/brown due to iron staining
Luster: Vitreous to greasy

Identified July 6, 2026More mineral →

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Physical properties

Formation & geological history

Formed from cooling silica-rich hydrothermal fluids in veins or as a late-stage crystallization in igneous rocks. This specific specimen appears to be a large, weathered chunk of vein quartz, potentially from the Precambrian or Paleozoic eras depending on the local bedrock.

Uses & applications

Used industrially as a source of silicon, as an abrasive, and in the manufacturing of glass and ceramics. Landscaping and decorative garden use are common for large raw specimens. High-purity quartz is essential in electronics.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German word 'quarz', which originally meant 'hard'. Large massive white quartz is often nicknamed 'bull quartz' by miners because it is tough to mine through but often contains no valuable ore.

Field identification & locations

Identify by its hardness (it will easily scratch glass and stainless steel) and its lack of cleavage. Look for a greasy luster on freshly broken surfaces. It is found globally, particularly in mountainous regions and riverbeds as erodes out of quartz veins.