mineral

Quartz (Iron-Stained or Milky Quartz)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Translucent white with brownish-yellow iron staining; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Translucent white with brownish-yellow iron staining
Luster: Vitreous to greasy

Identified March 22, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silica-rich hydrothermal fluids cooling in veins/cracks or as a primary mineral in igneous and metamorphic rocks. Most common in ancient Precambrian or Paleozoic geological environments.

Uses & applications

Used in manufacturing glass, ceramics, and electronics (quartz oscillators). Low-grade pebbles are often used as industrial abrasives or landscaping gravel. Tumbled pieces are common in beginner rock collections.

Geological facts

Quartz is the second most abundant mineral in the Earth\'s continental crust. Pure quartz is clear (Rock Crystal), but micro-impurities of iron or contact with groundwater causes the yellowish-brown staining seen on this specimen.

Field identification & locations

Identify by its ability to scratch glass and lack of cleavage planes. Found globally in riverbeds, soil, and outcrops. For collectors, it is a staple find that demonstrates the durability of silicate minerals against weathering.

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