mineral

Milky Quartz with Algae/Iron Staining

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: White to yellowish-green due to surface staining; Luster: Vitreous to greasy; Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct/Conchoidal fracture; Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: White to yellowish-green due to surface staining
Luster: Vitreous to greasy

Identified July 9, 2026More mineral →

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Physical properties

Formation & geological history

Found in hydrothermal veins and pegmatites. This specimen likely weathered out of a vein and spent time in a damp or river environment, leading to the green algae growth and iron oxide staining on the surface.

Uses & applications

Used in glassmaking, abrasives, and as a common 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 cloudiness from tiny fluid inclusions of gas or liquid trapped during crystal growth.

Field identification & locations

Identify by its hardness (it will scratch glass) and lack of cleavage. Common in riverbeds and mountainous regions globally. Look for the waxy or glassy luster on fresh breaks.

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Sandstone with Mineral Veining or Crust

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Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

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Gypsum (variety Selenite or Alabaster)

Calcium sulfate dihydrate (CaSO4·2H2O)

Mineral

Nephrite Jade

Nephrite

Mineral/Rock