mineral

Banded Agate (Tumbled)

Silicon Dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale), Color: Brown, cream, and white bands, Luster: Waxy to vitreous when polished, Crystal Structure: Hexagonal (cryptocrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.64

Hardness: 6

Identified June 24, 2026More mineral →

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Physical properties

Formation & geological history

Formed in cavities within volcanic rocks or ancient lavas, where silica-rich groundwater deposited layers over time. Agates are typically millions of years old, often dating to the Tertiary or Cretaceous periods.

Uses & applications

Primarily used in jewelry, as decorative pocket stones (worry stones), in lapidary art, and for metaphysical purposes. Historically used for making knife edges and ornaments.

Geological facts

The name 'Agate' comes from the Achates River in Sicily, where agates were first discovered. Banded agates are a variety of chalcedony where each layer represents a different pulse of mineral-rich water.

Field identification & locations

Identify by its characteristic colorful banding and waxy surface. It is commonly found in Brazil, India, and the United States (specifically Lake Superior and Oregon). Field identification involves checking for translucency and concentric banding patterns when a cross-section is visible.