mineral

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: White to translucent; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7 (Mohs scale)
Color: White to translucent
Luster: Vitreous to waxy

Identified May 3, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: White to translucent; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Formation & geological history

Formed through the precipitation of minerals from hydrothermal fluids or groundwater within cavities of volcanic or sedimentary rocks. Over time, crystals grow inward from the cavity walls, often leaving a hollow center.

Uses & applications

Primarily used for geological education, lapidary work, jewelry making (when polished), and as ornamental display pieces in mineral collections.

Geological facts

The word geode is derived from the Greek word 'Geoides' meaning earth-like. Unlike a solid rock, the interior of a geode can contain many different crystal types, most commonly quartz, amethyst, or chalcedony.

Field identification & locations

Identify in the field by looking for rounded, lumpy nodules with a distinct outer rind that differs from the surrounding matrix. When broken, they reveal a crystalline interior. Commonly found in desert regions, volcanic ash beds, and limestone deposits.