mineral

Chalcedony (Botryoidal or Chalcedony Rose)

Silicon dioxide (SiO2)

Hardness: 6.5-7 Mohs; Color: Pale pink to white; Luster: Waxy to vitreous; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific Gravity: 2.6-2.64

Hardness: 6
Color: Pale pink to white
Luster: Waxy to vitreous

Identified June 23, 2026More mineral →

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Physical properties

Hardness: 6.5-7 Mohs; Color: Pale pink to white; Luster: Waxy to vitreous; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific Gravity: 2.6-2.64

Formation & geological history

Formed from the deposition of silica-rich water in cavities of volcanic rocks or sedimentary environments. The botryoidal (grape-like) habit occurs as silica precipitates around a core or along a surface.

Uses & applications

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

Geological facts

This bubbly, rounded growth pattern is called 'botryoidal' from the Greek word for 'bunch of grapes'. Chalcedony is the cryptocrystalline form of quartz, meaning its crystals are too small to see with a standard microscope.

Field identification & locations

Identify by its waxy luster, smooth rounded surfaces, and the fact that it cannot be scratched by a steel knife. Found globally, extensively in the southwestern USA, Brazil, and Namibia.

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