Rock Identifier
Milky Quartz (Silicon Dioxide (SiO2)) — mineral
mineral

Milky Quartz

Silicon Dioxide (SiO2)

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

Hardness
7 on Mohs scale
Color
Opaque white to translucent
Luster
Vitreous to greasy
Identified More mineral
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Physical properties

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

Formation & geological history

Formed in hydrothermal veins and pegmatites. The white color is caused by tiny inclusions of gas or liquid trapped during crystal growth. Can be found in igneous, metamorphic, and sedimentary environments.

Uses & applications

Used in glassmaking, ceramics, electronics (source of silicon), ornamental stone, and as a popular specimen for beginner rock collectors.

Geological facts

Milky Quartz is the most common variety of crystalline quartz. It is often found in large veins that can extend for miles through darker host rocks like granite or schist.

Field identification & locations

Identify by its white color, ability to scratch glass (hardness 7), and lack of cleavage. It is found globally in riverbeds, mountains, and beaches.