Mineral

Yellow Chalcedony (Carnelian/Yellow Agate)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Hardness: 6.5–7 (Mohs scale); Color: Yellow to golden-orange; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (trigonal) microcrystalline; Cleavage: None; Specific Gravity: 2.58–2.64.

Hardness: 6
Color: Yellow to golden-orange
Luster: Vitreous to waxy

Identified March 24, 2026More mineral →

Identify your own rocks.

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

App Store Google Play

Physical properties

Hardness: 6.5–7 (Mohs scale); Color: Yellow to golden-orange; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (trigonal) microcrystalline; Cleavage: None; Specific Gravity: 2.58–2.64.

Formation & geological history

Formed through the deposition of silica from groundwater in cavities of igneous or sedimentary rocks. This specimen is likely from a volcanic or hydrothermal environment where silica-rich fluids cooled slowly. Geologically, these can range from very young to hundreds of millions of years old.

Uses & applications

Primarily used in jewelry as cabochons, beads, and carvings. Also used in industrial applications for precision bearings and pivot points due to its hardness, and highly valued by gem collectors.

Geological facts

Yellow chalcedony is often associated with sun deities in ancient cultures. While technically a form of Agate if banded, when it is solid and translucent like this, it is referred to simply as Chalcedony. The yellow hue is often caused by trace amounts of iron hydroxides (limonite).

Field identification & locations

Identify by its waxy luster, translucency, and lack of visible crystal faces. It is common in regions with volcanic activity like India, Brazil, and Madagascar. Collectors look for uniform color and high translucency with minimal internal inclusions.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

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

Epidote

Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

mineral