mineral

Chalcedony (Agate/Carnelian variant)

Silicon Dioxide (SiO2)

Hardness: 6.5-7 on Mohs scale. Color: Translucent orange to brown with dark dendritic or manganese inclusions. Luster: Waxy to vitreous. Crystal structure: Cryptocrystalline (Trigonal/Monoclinic). Cleavage: None, exhibits conchoidal fracture.

Hardness: 6
Luster: Waxy to vitreous

Identified June 17, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed through the deposition of silica from groundwater in cavities of volcanic or sedimentary rocks. This specimen likely formed in a low-temperature hydrothermal environment.

Uses & applications

Commonly used in lapidary work for making cabochons, beads, and ornamental carvings. It is also a popular specimen for rock tumbling and amateur collecting.

Geological facts

Chalcedony was one of the first materials used by early humans to create tools and weapons because of its toughness and predictable fracture patterns. The orange variety is specifically known as Carnelian.

Field identification & locations

Identify by its waxy luster, translucency when held to light, and its inability to be scratched by a steel knife. It is frequently found in riverbeds, desert pavements, and volcanic ash deposits.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral