mineral

Quartz Geode Fragment

Silicon Dioxide (SiO2)

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

Hardness: 7 on Mohs scale
Color: Clear to white
Luster: Vitreous (glassy)

Identified July 18, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed as secondary mineral precipitates from hydrothermal fluids inside cavities (drusy) of host rocks. These cavities are often created by gas bubbles in volcanic rock or the dissolution of nodules in sedimentary rock, occurring over millions of years.

Uses & applications

Used primarily for home decor, educational specimens, metaphysical purposes, and as a source of high-purity silica for the electronics industry in some industrial cases.

Geological facts

Geodes are often called 'thunder eggs.' While the exterior looks like a common rock, the interior reveals a hollow cavity lined with sparkling crystals. This specific specimen shows druzy quartz crystals.

Field identification & locations

Identify by its hardness (will scratch glass) and lack of cleavage. Look for the distinct sparkling crystalline texture within a hollow or vug. Common in regions with ancient volcanic activity or limestone beds, such as Brazil, Uruguay, and the Midwest US.