sedimentary

Banded Agate (Jasper-Agate)

Silicon Dioxide (SiO2)

Hardness: 6.5-7 on Mohs scale. Color: Multicolored bands of orange, red, black, and translucent white. Luster: Vitreous to waxy when polished. Crystal structure: Trigonal (microcrystalline quartz). Cleavage: None (conchoidal fracture). Specific Gravity: 2.58-2.64.

Hardness: 6
Luster: Vitreous to waxy when polished

Identified May 26, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in cavities within volcanic or sedimentary rocks through the deposition of silica from groundwater. The bands represent different stages of mineral deposition over thousands of years. Often found in ancient volcanic deposits spanning from the Precambrian to Cenozoic eras.

Uses & applications

Used widely in jewelry (cabochons and beads), decorative ornaments, stone carving, and as 'pocket stones' for crystal collectors. Historically used for making mortars and pestles due to its hardness.

Geological facts

The distinct banding is caused by variations in the impurities present during the slow precipitation of silica. Metaphysically, many cultures throughout history believed agate provided protection and strength. The Lake Superior Agate is a famous regional variety with similar coloring.

Field identification & locations

Identify in the field by its smooth, waxy texture and characteristic parallel banding when broken or polished. It will scratch glass but cannot be scratched by a steel knife. Common in riverbeds, lake shores, and volcanic outcroppings worldwide.

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