mineral

Milky Quartz Geode / Chalcedony Nodule

Quartz (Silicon Dioxide - SiO2)

Hardness: 7 on Mohs scale. Color: Milky white exterior with a translucent to brownish/crystalline central cavity. Luster: Vitreous to greasy. Crystal System: Trigonal/Hexagonal. Cleavage: None (conchoidal fracture). Specific Gravity: ~2.65.

Hardness: 7 on Mohs scale
Luster: Vitreous to greasy

Identified July 27, 2026More mineral →

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Physical properties

Formation & geological history

Forms in cavity spaces within volcanic or sedimentary rocks where silica-rich hydrothermal fluids precipitate quartz crystals layer by layer over extended geological periods.

Uses & applications

Widely collected as decorative natural mineral specimens, lapidary material for tumbling/polishing, and educational samples.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Small geode cavities like this often house tiny quartz druzy crystals or microcrystalline chalcedony layers.

Field identification & locations

Identified by its high hardness (scratches glass easily and cannot be scratched by a steel knife), lack of cleavage, and characteristic milky white rind enclosing a crystalline or chalcedonic interior void. Extremely common worldwide, found in stream beds, gravel deposits, and weathered rock outcrops.

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