Botryoidal Quartz / Calcite Geode crust

Physical Properties

Hardness: 7 (if quartz) or 3 (if calcite); Color: White, cream, or colorless; Luster: Vitreous to pearly; Crystal structure: Trigonal or Hexagonal; Specific gravity: 2.65 or 2.71

Formation & Geological History

Formed through hydrothermal precipitation in rock cavities or vugs, where mineral-rich water slowly deposits layers over thousands of years.

Uses & Applications

Commonly used for geological displays, decorative home decor, crystal healing collections, and educational specimens.

Geological Facts

Botryoidal formations get their name from the Greek word 'botrys', meaning a bunch of grapes, due to the rounded, bubbly appearance of the mineral growth.

Field Identification & Locations

Identified by its cauliflower-like or 'bubbly' texture. To distinguish between quartz and calcite, one can perform an acid test (calcite fizzes) or a hardness test (quartz scratches glass).

Identified on: 4/14/2026

Mode: Standard