mineral

Quartz (Milky or Yellowish)

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 July 6, 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

Quartz forms in a variety of environments, primarily through the cooling of silica-rich magma or from hydrothermal veins. It is found in igneous, metamorphic, and sedimentary rocks globally and can be billions of years old.

Uses & applications

Used extensively in the glassmaking and electronics industries (piezoelectric properties), as an abrasive, in construction as sand/aggregate, and as a semi-precious gemstone in jewelry.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German word 'Quarz', which has Slavic origins meaning 'hard'. It is resistant to chemical weathering.

Field identification & locations

Identify by its hardness (it will scratch glass), conchoidal fracture (curved breakages), and lack of cleavage. Often found as rounded pebbles in riverbeds or as mass veins in mountain outcrops.