mineral

Agate (Carnelian-like)

Chalcedony (Silicon Dioxide, SiO2)

Hardness: 6.5-7 on the Mohs scale; Color: Translucent grey to reddish-brown; Luster: Waxy to vitreous; Crystal Structure: Cryptocrystalline (Trigonal); Cleavage: None; Specific Gravity: 2.58–2.64

Hardness: 6
Color: Translucent grey to reddish-brown
Luster: Waxy to vitreous

Identified April 8, 2026More mineral →

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Physical properties

Hardness: 6.5-7 on the Mohs scale; Color: Translucent grey to reddish-brown; Luster: Waxy to vitreous; Crystal Structure: Cryptocrystalline (Trigonal); Cleavage: None; Specific Gravity: 2.58–2.64

Formation & geological history

Formed through the deposition of silica from groundwater into cavities (vesicles) of igneous rocks or sedimentary layers. This specimen shows iron oxide staining common in arid environments.

Uses & applications

Used primarily in lapidary arts for jewelry, decorative carvings, and as a semi-precious collector's stone. Also historically used for making precision bearings and mortars.

Geological facts

Agate is a variety of chalcedony characterized by its microcrystalline structure. The red coloration in the center is likely caused by iron impurities, similar to Carnelian.

Field identification & locations

Identify by its waxy appearance and conchoidal fracture (smooth, curved breaks). Common in riverbeds and volcanic regions. Collectors look for banding and clarity.

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