mineral

Chalcedony (Desert Rose or Botryoidal Chalcedony)

Silicon Dioxide (SiO2)

Hardness: 6.5–7 (Mohs scale); Color: White, milky, or waxy; Luster: Waxy to dull; Crystal structure: Trigonal (cryptocrystalline); Cleavage: None; Specific Gravity: 2.6–2.64

Hardness: 6
Color: White, milky, or waxy
Luster: Waxy to dull

Identified April 19, 2026More mineral →

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Physical properties

Hardness: 6.5–7 (Mohs scale); Color: White, milky, or waxy; Luster: Waxy to dull; Crystal structure: Trigonal (cryptocrystalline); Cleavage: None; Specific Gravity: 2.6–2.64

Formation & geological history

Formed from the deposition of silica from groundwater in the cavities of volcanic rocks or sedimentary formations. This specimen shows botryoidal (grape-like) or 'desert rose' style growth common in arid environments.

Uses & applications

Used primarily for lapidary work, jewelry (cabochons), and as a decorative specimen for collectors.

Geological facts

Chalcedony is a cryptocrystalline form of silica, meaning its crystals are too small to be seen under a normal microscope. It was highly prized in antiquity for cylinder seals in Mesopotamia.

Field identification & locations

Identify by its waxy luster, hardness (it can scratch glass), and lack of visible crystals. Commonly found in desert regions or basaltic volcanic fields. Collectors look for unique petal-like shapes or translucency.

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