mineral

Milky Quartz

Quartz (SiO2) with iron staining

Hardness: 7 (Mohs scale); Color: White, tan, or gray with orange/brown iron staining; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); SG: 2.65

Hardness: 7 (Mohs scale)
Color: White, tan, or gray with orange/brown iron staining
Luster: Vitreous to greasy

Identified May 29, 2026More mineral →

Identify your own rocks.

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

App Store Google Play

Physical properties

Hardness: 7 (Mohs scale); Color: White, tan, or gray with orange/brown iron staining; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); SG: 2.65

Formation & geological history

Formed via hydrothermal activity where silicon-rich fluids crystallize in rock fractures or veins. The iron staining occurs when the specimen is exposed to groundwater containing iron oxides. Geological age varies globally from Precambrian to Cenozoic.

Uses & applications

Used industrially in glass manufacturing, electronics (due to piezoelectricity), and as an abrasive. In lapidary, it is used for carvings and decorative stones. This specific raw specimen is primarily for collecting.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz gets its opaque white color from tiny pocket inclusions of gas or liquid trapped during crystal growth.

Field identification & locations

Identify in the field by its hardness (cannot be scratched by steel) and lack of cleavage. It is found globally in almost any environment, especially creek beds and mountainous areas. Focus on the grainy, crystalline texture and the way it breaks along curved surfaces.