mineral

Botryoidal Agate / Chalcedony Geode

Silicon Dioxide (SiO2)

Hardness: 6.5-7 on Mohs scale. Color: Translucent white, gray, and tan. Luster: Waxy to vitreous. Crystal Structure: Hexagonal (cryptocrystalline). Cleavage: None (conchoidal fracture).

Hardness: 6
Color: Translucent white, gray, and tan
Luster: Waxy to vitreous

Identified May 2, 2026More mineral →

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Physical properties

Hardness: 6.5-7 on Mohs scale. Color: Translucent white, gray, and tan. Luster: Waxy to vitreous. Crystal Structure: Hexagonal (cryptocrystalline). Cleavage: None (conchoidal fracture).

Formation & geological history

Formed via the deposition of silica from groundwater in cavities of igneous or sedimentary rocks. The rounded, grape-like shapes (botryoidal) grow outwards from nucleation points within a void.

Uses & applications

Used primarily for lapidary work, jewelry making (cabochons), and as decorative cabinet specimens for mineral collectors.

Geological facts

The term 'botryoidal' comes from the Greek word 'botrys', meaning a bunch of grapes. These specimens often form the interior lining of geodes or vugs.

Field identification & locations

Identify by the characteristic bubbly or rounded surface texture and waxy luster. Commonly found in volcanic regions or limestone deposits globally.

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