mineral

Milky and Ferruginous Quartz

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Orange-brown (iron-stained), white, and colorless; Luster: Vitreous to greasy; Crystal Structure: Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Orange-brown (iron-stained), white, and colorless
Luster: Vitreous to greasy

Identified July 15, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silica-rich hydrothermal solutions cooling in crustal fractures or as a primary constituent in igneous rocks. Iron oxide staining occurs due to groundwater interaction during weathering.

Uses & applications

Used primarily for mineral collecting, as a source of silica for glassmaking, and potentially for lapidary work if high quality.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Specimens like this one, showing both milky quartz and iron staining, are common indicators of geological veins.

Field identification & locations

Identify by its hardness (scratches glass), lack of cleavage, and crystal face remnants. Found globally, especially in mountain ranges and creek beds near igneous or metamorphic outcrops.