mineral

Chalcedony Geode Fragment (Botryoidal)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Hardness: 6.5-7 Mohs scale; Color: Milky white to greyish-blue; Luster: Waxy to vitreous; Crystal Structure: Trigonal (microscopic); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.64.

Hardness: 6
Color: Milky white to greyish-blue
Luster: Waxy to vitreous

Identified June 11, 2026More mineral →

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Physical properties

Hardness: 6.5-7 Mohs scale; Color: Milky white to greyish-blue; Luster: Waxy to vitreous; Crystal Structure: Trigonal (microscopic); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.64.

Formation & geological history

Formed through the deposition of silica-rich groundwater in the volcanic cavities or sedimentary pockets. These often grow in layers over thousands of years, typically in Tertiary or Cretaceous formations.

Uses & applications

Primarily used for geological collecting, educational displays, and sometimes tumbled for lapidary use or jewelry making.

Geological facts

The bubbly, grape-like appearance is called 'botryoidal' texture. This specimen specifically shows 'agate' layering within a small vug or geode pocket.

Field identification & locations

Identify by its waxy luster, hardness (it will scratch glass), and the rounded botryoidal internal surface. Common in volcanic regions with high mineral turnover.

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