sedimentary (chemical/biological origin)

Green Jasper with Agate Banding

Silicon Dioxide (SiO2) with impurities of ferrous silicate or chlorite

Hardness: 6.5-7 Mohs. Color: Sea-green with lighter green concentric banding. Luster: Dull/waxy (unpolished) to vitreous (polished). Crystal structure: Microcrystalline/Cryptocrystalline. Cleavage: None (conchoidal fracture).

Hardness: 6
Color: Sea-green with lighter green concentric banding
Luster: Dull/waxy (unpolished) to vitreous (polished)

Identified March 24, 2026More sedimentary (chemical/biological origin) →

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Physical properties

Formation & geological history

Formed from the precipitation of silica from fluid in cavities of volcanic rocks or sedimentary environments. These microcrystalline quartz varieties often form in the Precambrian and Paleozoic eras as hydrothermal fluids flow through rock fissures.

Uses & applications

Used primarily in lapidary arts for jewelry, cabochons, and decorative ornamental items. Also highly valued as pocket stones and for metaphysical collecting.

Geological facts

Jasper was a favorite gem in the ancient world, referenced in many historical texts. The green variety is specifically known as 'orbicular' or 'banded' jasper when it shows circular patterns like the specimen pictured.

Field identification & locations

Identify in the field by its extreme hardness (cannot be scratched by a steel knife) and its smooth, water-worn texture on beaches or riverbeds. Common in the Pacific Northwest (USA), India, and Brazil. Collectors should look for unique 'eyes' or ring patterns.

Other sedimentary (chemical/biological origin) specimens

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Jasper (specifically Polychrome or Desert Jasper)

Silicon Dioxide (SiO2) with iron oxide and other mineral impurities

sedimentary (chemical/biological origin)

Red Jasper (Plum or Brick variety)

Silicon Dioxide (SiO2) with iron oxide inclusions (Hematite)

sedimentary (chemical/biological origin)

Jasper (Wonderstone/Banded Jasper)

Silicon Dioxide (SiO2) with iron oxide impurities

sedimentary (chemical/biological origin) or volcanic-related metamorphic

Chert (and Flint)

Silicon Dioxide (SiO2)

sedimentary

Limestone (specifically Marl or Chalk)

Calcium Carbonate (CaCO3)

sedimentary

Note: Item is not a geological specimen

Homo sapiens (Dermal Appendage: Pilus)

Organic / Biological