mineral

Quartz (Iron-stained or Milky)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: White to brownish-orange (due to iron oxide staining); Luster: Vitreous to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: White to brownish-orange (due to iron oxide staining)
Luster: Vitreous to greasy

Identified July 1, 2026More mineral →

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Physical properties

Formation & geological history

Forms in igneous, metamorphic, and sedimentary environments. Most commonly crystallizes from cooling magma or precipitates from hydrothermal veins. Staining occurs when iron-rich water seeps into fractures over time.

Uses & applications

Used in glass manufacturing, electronics (piezoelectric properties), abrasives, and as semi-precious gemstones in jewelry or for decorative collection.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Iron-stained varieties are often mistaken for gold or amber by beginners but are much harder and more common.

Field identification & locations

Identify in the field by its hardness (will scratch glass and steel), lack of cleavage, and translucent appearance. It is found globally in riverbeds, mountains, and mines.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

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

metamorphic

Gypsum (variety Selenite or Alabaster)

Calcium sulfate dihydrate (CaSO4·2H2O)

Mineral

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

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

Metamorphic Rock