sedimentary

Tumbled Agate

Cryptocrystalline Quartz (SiO2)

Hardness: 6.5-7 on Mohs scale. Color: Translucent grey with banded yellow/brown inclusions. Luster: Waxy to vitreous. Crystal structure: Trigonal/Microcrystalline. Specific gravity: 2.58-2.64.

Hardness: 6
Color: Translucent grey with banded yellow/brown inclusions
Luster: Waxy to vitreous

Identified July 10, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 on Mohs scale. Color: Translucent grey with banded yellow/brown inclusions. Luster: Waxy to vitreous. Crystal structure: Trigonal/Microcrystalline. Specific gravity: 2.58-2.64.

Formation & geological history

Formed primary in volcanic rocks or ancient hydrothermal veins where silica-rich groundwater fills cavities (vesicles). The banding represents different stages of mineral deposition over time.

Uses & applications

Commonly used in jewelry, ornamental carvings, lapidary art, and as healing crystals in the metaphysical community. Historically used for making knife edges and mortars/pestles.

Geological facts

Agates are named after the Achates River in Sicily. They are known for their distinct banding patterns, though tumbled stones often show these as subtle internal swirls or 'cloud' patterns.

Field identification & locations

Identify by its hardness (can scratch glass), translucency, and waxy luster. In the field, look for nodules with a rough exterior but a translucent, colorful interior when broken or polished.