mineral

Quartz (Double-Terminated)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Colorless to milky white/tan; Luster: Vitreous (glass-like); Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Colorless to milky white/tan
Luster: Vitreous (glass-like)

Identified March 15, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Colorless to milky white/tan; Luster: Vitreous (glass-like); Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Formation & geological history

Formed in cavities or soft host rocks where the crystal can grow without attaching to a matrix, allowing it to develop points on both ends. Often found in dolostone or sedimentary pockets dating from the Cambrian to Devonian periods.

Uses & applications

Commonly used in jewelry (wire-wrapped or as 'Herimer' style specimens), meditation/metaphysical collecting, and as a source of silica for glass and electronics (though usually industrial quartz is crushed).

Geological facts

Double-terminated quartz crystals are rare in nature because crystals usually grow attached to a rock wall. The most famous variety is the 'Herkimer Diamond' from New York, though similar specimens are found globally.

Field identification & locations

Identify in the field by looking for a 'six-sided' hexagonal prism shape with points at both ends. Frequently found in 'vugs' or loose in soil near limestone/dolomite outcrops. Commonly found in Upstate New York, Arkansas, and Pakistan.