mineral

Quartz (Milky or Smoky Quartz)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Grayish-white to tan with smokey/translucent portions; Luster: Vitreous to greasy; Crystal structure: Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Grayish-white to tan with smokey/translucent portions
Luster: Vitreous to greasy

Identified June 21, 2026More mineral →

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Physical properties

Formation & geological history

Forms in a variety of environments from cooling magma (igneous) to hydrothermal veins and metamorphic rocks. This specimen likely weathered out of a quartz vein in a larger rock formation.

Uses & applications

Quartz is used in glassmaking, abrasives, jewelry (semiprecious stones), and the electronics industry for its piezoelectric properties. This rough specimen is mainly and of hobbyist interest.

Geological facts

Quartz is one of the most abundant and diverse minerals on Earth's crust. It is highly resistant to chemical and physical weathering, which is why it often remains as pebbles/cobbles long after surrounding rocks have eroded.

Field identification & locations

Identify in the field by its hardness (will scratch glass and steel), lack of cleavage, and waxy/vitreous luster. Found globally in almost all geological terrains. Look for its characteristic fracture pattern.

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