mineral

Chalcedony (specifically Agate or Carnelian)

Silicon Dioxide (SiO2)

Hardness: 6.5–7; Color: Orange-brown, translucent with waxy luster; Crystal Structure: Microcrystalline (trigonal); Cleavage: None/Conchoidal fracture.

Hardness: 6
Color: Orange-brown, translucent with waxy luster

Identified June 17, 2026More mineral →

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Physical properties

Hardness: 6.5–7; Color: Orange-brown, translucent with waxy luster; Crystal Structure: Microcrystalline (trigonal); Cleavage: None/Conchoidal fracture.

Formation & geological history

Formed in cavities of volcanic rocks or sedimentary environments through the slow deposition of silica from groundwater. Often found in geode structures or as nodules.

Uses & applications

Commonly used in jewelry (cabochons), lapidary art, watch bearings, and as historical amulets/seals.

Geological facts

Carnelian was highly prized in ancient Rome and Egypt for signet rings because hot wax does not stick to it.

Field identification & locations

Identify by its waxy luster, translucency, and lack of visible grains. Found globally, especially in basalt flows, riverbeds, and beach deposits.

Other mineral specimens

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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