Blue Chalcedony (likely dyed Agate)

Physical Properties

Hardness: 6.5–7 (Mohs scale), Color: Inky blue to teal (likely enhanced), Luster: Waxy to vitreous, Crystal Structure: Trigonal (microcrystalline), Cleavage: None, Specific Gravity: 2.60–2.64

Formation & Geological History

Formed in volcanic and sedimentary environments through the deposition of silica from groundwater in rock cavities or veins. Common in geodes and volcanic bubbles.

Uses & Applications

Used primarily in lapidary work for cabochons, beads, and tumbled stones. Also popular in jewelry and metaphysical collections.

Geological Facts

Many intensely blue tumbled stones sold in shops are natural Brazilian agates that have been dyed to achieve a deep, uniform blue color, as natural blue chalcedony is typically paler and more translucent.

Field Identification & Locations

Identify by its waxy luster, conchoidal fracture (visible in chips), and its ability to scratch glass but not quartz. Commonly found in Brazil, India, and Madagascar.

Identified on: 4/26/2026

Mode: Standard