Rock Identifier
Green Chalcedony (likely Green Agate or Chrysoprase) (Silicon Dioxide (SiO2) - Microcrystalline Quartz) — Mineral
Mineral

Green Chalcedony (likely Green Agate or Chrysoprase)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Hardness: 6.5–7 on Mohs scale; Color: Translucent to opaque deep green; Luster: Vitreous to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None; Specific gravity: 2.60–2.65.

Hardness
6
Color
Translucent to opaque deep green
Luster
Vitreous to waxy
Identified More mineral →

Identify your own rocks.

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

App StoreGoogle Play

Physical properties

Hardness: 6.5–7 on Mohs scale; Color: Translucent to opaque deep green; Luster: Vitreous to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None; Specific gravity: 2.60–2.65.

Formation & geological history

Formed in volcanic and sedimentary environments via hydrothermal activity. Silica-rich fluids deposit in rock cavities or fractures over millions of years at relatively low temperatures.

Uses & applications

Primarily used as a gemstone for jewelry (cabochons), ornamental carvings, and historical talismans for over 3,000 years.

Geological facts

Green chalcedony was highly prized in ancient Greece and Rome. When the green color is derived from nickel, it is specifically called Chrysoprase; if it is artificially dyed (common in commercial jewelry), it is labeled Green Agate.

Field identification & locations

Identify by its waxy luster, lack of visible crystals, and conchoidal (shell-like) fracture. In the field, look for smooth, rounded nodules or veins in weathered volcanic rock. Common locations include Brazil, India, and Australia.

More like this

Other mineral specimens

Sandstone (with potential mineral staining/concretions) (Arenite (SiO2 based)) — sedimentary

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

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

Epidote

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

metamorphic
Nephrite Jade (Nephrite) — Mineral/Rock

Nephrite Jade

Nephrite

Mineral/Rock
Banded Gneiss (River Rock/Pebble) (Gneiss (specifically a banded variety often found as a river rock)) — Metamorphic 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

Green Apatite on Albite

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

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

Epidote

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

mineral