Metamorphic or Mineral

Quartz / Quartzite

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: white to light tan; Luster: vitreous to waxy; Crystal structure: hexagonal/trigonal; Cleavage: none (conchoidal fracture); Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: white to light tan
Luster: vitreous to waxy

Identified April 4, 2026More metamorphic or mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: white to light tan; Luster: vitreous to waxy; Crystal structure: hexagonal/trigonal; Cleavage: none (conchoidal fracture); Specific gravity: 2.65.

Formation & geological history

Formed through the metamorphism of quartz-rich sandstone or as a hydrothermal vein mineral. It is common throughout all geological ages, found in mountain belts where intense heat and pressure recrystallize sandstone.

Uses & applications

Used as a primary source of silica in glassmaking, as a construction aggregate, for railroad ballast, and sometimes in decorative landscaping.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartzite is extremely durable and resistant to chemical weathering.

Field identification & locations

Identify by its hardness (it will scratch glass and steel) and lack of reaction to acid. It is commonly found in riverbeds, crushed stone piles, and mountain outcrops. For collectors, look for crystal faces or high purity.

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Kyanite

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Silicon Dioxide (SiO2) within a metamorphic matrix

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Slate

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Tiger's Eye and Carnelian Quartz

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