mineral

Tumbled Agate and Chalcedony

Cryptocrystalline Quartz (SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Multi-colored (white, gray, honey, blue, brown); Luster: Vitreous to waxy; Crystal Structure: Hexagonal (trigonal); Cleavage: None/Conchoidal fracture; Specific Gravity: 2.60-2.65.

Hardness: 6
Color: Multi-colored (white, gray, honey, blue, brown)
Luster: Vitreous to waxy

Identified June 28, 2026More mineral →

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Physical properties

Formation & geological history

Formed primary in volcanic and metamorphic environments from silica-rich groundwater filling cavities (vugs) or veins. They often develop as rhythmic layers of microcrystalline quartz.

Uses & applications

Commonly used for lapidary arts, decorative items, tumbled pocket stones, metaphysical jewelry, and as industrial abrasives.

Geological facts

Agate is a variety of chalcedony characterized by its banding. The name comes from the Achates River in Sicily where agates were first discovered in ancient times.

Field identification & locations

Identify by its translucent to opaque nature, waxy luster, and lack of cleavage. Often found in riverbeds, beaches, or weathered volcanic soils. Use a hardness test to distinguish from glass or plastic (agate will scratch glass).

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

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metamorphic

Gypsum (variety Selenite or Alabaster)

Calcium sulfate dihydrate (CaSO4·2H2O)

Mineral

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

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

Metamorphic Rock