Purple Chalcedony (likely dyed Agate)

Physical Properties

Hardness: 6.5-7 (Mohs), Color: Deep purple (artificially enhanced), Luster: Vitreous to waxy, Crystal Structure: Hexagonal (trigonal microcrystalline), Specific Gravity: 2.6-2.65

Formation & Geological History

Forms in volcanic and sedimentary rocks as nodules or veins from silica-rich groundwater. Most deep purple chalcedony cabochons in jewelry are created by staining porous natural agate with iron or chromium salts.

Uses & Applications

Primarily used in jewelry as cabochons, beads, and ornamental carvings; also popular in spiritual/metaphysical collecting.

Geological Facts

Chalcedony is a cryptocrystalline form of silica. While natural purple chalcedony (like 'Grape Agate' or 'Holly Blue') exists, the uniform saturated color and 'orbicular' circular banding visible in this specimen suggest it is a dyed Brazilian agate.

Field Identification & Locations

Identify by its waxy luster and inability to be scratched by a steel blade. In the field, look for botryoidal (grape-like) textures in volcanic cavities. Commonly found in Brazil, India, and Madagascar.

Identified on: 4/29/2026

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