mineral

Milky Quartz with Iron Staining

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to translucent with yellow/ochre iron staining; Luster: Vitreous to greasy; Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Milky white to translucent with yellow/ochre iron staining
Luster: Vitreous to greasy

Identified April 29, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the cooling of silica-rich hydrothermal fluids in veins or pegmatites. The yellow coloring is due to secondary iron oxide (limonite or hematite) coating the surface or filling internal fractures.

Uses & applications

Primarily used in glass making, ceramics, and as an abrasive. While common quartz has low individual jewelry value, it is a key indicator for gold prospecting and is popular among beginning collectors.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Iron-stained quartz is often called 'gold quartz' or 'rusty quartz' by prospectors because it indicates the presence of hydrothermal activity where gold might be found.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), its conchoidal (shell-like) fracture, and its lack of cleavage. Often found in riverbeds or near mountain outcrops.

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Arenite (SiO2 based)

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Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

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mineral