mineral

Quartz Geode

Silicon Dioxide (SiO2)

Hardness of 7 on the Mohs scale, clear to white color with a vitreous (glassy) luster, trigonal crystal system, conchoidal fracture with no true cleavage, and a specific gravity of 2.65.

Identified August 6, 2026More mineral →

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Physical properties

Hardness of 7 on the Mohs scale, clear to white color with a vitreous (glassy) luster, trigonal crystal system, conchoidal fracture with no true cleavage, and a specific gravity of 2.65.

Formation & geological history

Formed inside hollow cavities in sedimentary or volcanic rocks where silica-rich groundwater gradually precipitates quartz crystals over millions of years.

Uses & applications

Used primarily in lapidary arts, jewelry, spiritual practices, and as a popular specimen for mineral collectors.

Geological facts

Geodes start as bubbles in volcanic rock or nodules in limestone that slowly fill with mineral-bearing water, allowing crystals to grow inward toward the center.

Field identification & locations

Often found in limestone formations or volcanic deposits worldwide; identifiable by its outer rind and hollow, crystal-lined interior revealed when cracked open.