mineral

Milky Quartz with Iron Inclusions

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: White to opaque white with yellowish-brown iron oxide staining; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: Poor/Conchoidal fracture; Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Luster: Vitreous to greasy

Identified May 30, 2026More mineral →

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Physical properties

Formation & geological history

Forms in hydrothermal veins or as a constituent of igneous and metamorphic rocks. Milky color is caused by minute fluid inclusions of gas or liquid trapped during crystal growth. Iron staining occurs through oxidation of associated minerals.

Uses & applications

Used in glass making, abrasives, gemstones (cabochons), and as landscaping stone. High-purity quartz is used in electronics for its piezoelectric properties.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. 'Milky' quartz gets its appearance from microscopic bubbles of water or CO2 that scatter light.

Field identification & locations

Identify by its hardness (it will scratch glass), its white opaque color, and lack of cleavage. Commonly found in gravel pits, stream beds, and mountain outcrops globally. Look for iron staining (rusty patches) which often indicates the presence of other associated minerals.

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

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Epidote

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metamorphic

Nephrite Jade

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Mineral/Rock

Banded Gneiss (River Rock/Pebble)

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

Metamorphic Rock

Biotite Schist

Biotite-rich Schist [K(Mg,Fe)3AlSi3O10(F,OH)2]

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Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral