Carnelian Agate Nodule

Physical Properties

Hardness: 6.5-7 (Mohs); Color: Waxy reddish-orange, brown, and tan; Luster: Vitreous to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); SG: 2.58-2.64

Formation & Geological History

Formed in volcanic host rock cavities (vesicles) where silica-rich fluids deposited layers over time. Known examples are often from Tertiary age deposits.

Uses & Applications

Used primarily in lapidary work for cabochons, beads, jewelry, and as decorative display specimens for collectors.

Geological Facts

Carnelian has been used as a gemstone since the Bronze Age. The reddish tint comes from iron oxide impurities. This specific nodule shows the typical 'pit' texture on the exterior common in river-worn or weathered agates.

Field Identification & Locations

Identify in the field by its waxy luster, translucency when held to light, and superior hardness (it will scratch glass). Commonly found in river beds, beaches, and volcanic regions like Oregon or Brazil.

Identified on: 5/11/2026

Mode: Standard