mineral

Bull Quartz (Milky Quartz)

Quartz (Silicon Dioxide - SiO2)

Hardness: 7 on Mohs scale. Color: White to off-white with yellowish-brown iron staining. Luster: Vitreous to greasy. Crystal Structure: Hexagonal (often massive in this form). Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: White to off-white with yellowish-brown iron staining
Luster: Vitreous to greasy

Identified March 4, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed from the cooling of silica-rich hydrothermal fluids in veins or as a primary mineral in igneous pegmatites. The milky appearance is caused by tiny inclusions of gas or liquid trapped during crystal growth. Can be found in rocks from almost any geological age.

Uses & applications

Used in glass making, as an abrasive, in the production of silicon for electronics, and as decorative stone in landscaping or rough rock collections. In historical mining, it was often used as an indicator for finding gold-bearing veins.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz is the most common variety of crystalline quartz. Historically, it was sometimes referred to as 'low-grade quartz' when found without clear crystal terminations.

Field identification & locations

Identify in the field by its hardness (it will scratch glass and steel), lack of cleavage, and translucent white color. It is commonly found in mountainous regions, riverbeds as rounded pebbles, or protruding from eroded outcrops. Collectors look for iron staining (as seen here) which can sometimes indicate nearby mineralization.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

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

Green Apatite on Albite

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

mineral

Epidote

Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

mineral