mineral

Quartz Geode

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: White to clear crystals; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: White to clear crystals
Luster: Vitreous (glassy)

Identified May 18, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: White to clear crystals; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed in cavities (vugs) within igneous or sedimentary rocks. Over geological time, mineral-rich groundwater seeps into the cavity, precipitating crystals that grow inward from the shell. Ages vary widely depending on the host rock.

Uses & applications

Primarily used for geological education, home decor, and mineral collecting. High-purity quartz is also used in electronics and glass manufacturing.

Geological facts

Geodes appear like ordinary rounded stones from the outside; their beauty is only revealed when cracked open. Some of the world's largest quartz geodes can be several meters long.

Field identification & locations

Identify in the field by looking for rounded, hollow-feeling rocks or nodules with a bumpy exterior. Commonly found in desert regions or areas with volcanic history like Brazil, Uruguay, or the American Southwest.