mineral

Botryoidal Chalcedony Geode

Silicon Dioxide (SiO2) - Chalcedony / Cryptocrystalline Quartz

Hardness: 6.5-7 (Mohs scale), Color: Translucent grey to white, Luster: Waxy to vitreous, Structure: Cryptocrystalline with botryoidal (grape-like) habit, Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.64

Hardness: 6

Identified March 20, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the low-temperature deposition of silica-rich groundwater within cavities of volcanic or sedimentary rocks. The botryoidal texture occurs as mineral layers grow outward from multiple centers simultaneously.

Uses & applications

Commonly used in lapidary work for cabochons and beads, as decorative display mineral specimens, and in metaphysical collecting.

Geological facts

Chalcedony is a cryptocrystalline form of silica, meaning its crystals are too small to be seen under a standard microscope. The term 'botryoidal' is derived from the Greek word 'botrys', meaning a bunch of grapes.

Field identification & locations

Identify in the field by its waxy appearance, rounded 'bubbly' internal texture, and hardness (it will scratch glass). Often found in desert regions or areas with historical volcanic activity such as the Western US, Brazil, and Morocco.

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