mineral

Quartz (Milky or Yellow variety)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Creamy white to pale yellow; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Creamy white to pale yellow
Luster: Vitreous to greasy

Identified May 31, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Creamy white to pale yellow; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed through the crystallization of silica-rich hydrothermal solutions or magmatic cooling. It can be found in igneous, metamorphic, and sedimentary environments worldwide.

Uses & applications

Used in glassmaking, electronics (piezoelectric properties), abrasives, as a flux in metallurgy, and in lapidary work/jewelry.

Geological facts

Quartz is the second most abundant mineral in the Earth's continental crust. Milky quartz gets its cloudy appearance from minute fluid inclusions of gas or liquid trapped during crystal growth.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), lack of cleavage, and translucent appearance. Frequently found as water-worn pebbles in riverbeds or as veins in bedrock.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

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

metamorphic

Nephrite Jade

Nephrite

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]

metamorphic