Jasper (Banded Jasper)

Physical Properties

Hardness: 6.5-7 (Mohs); Color: Red, orange, yellow, and tan banding; Luster: Vitreous to waxy; Crystal structure: Microcrystalline/Cryptocrystalline; Cleavage: None/Conchoidal fracture; Specific Gravity: 2.58-2.91

Formation & Geological History

Formed from the deposition of silica-rich fluids in cavities or through the accumulation of silica-rich sediments. The banding occurs due to rhythmic precipitation of iron oxides and hydroxides during the stone's formation. These are often found as cobbles in riverbeds after eroding from volcanic or sedimentary host rocks.

Uses & Applications

Used primarily as a gemstone for jewelry, lapidary arts (cabochons), and decorative ornamental objects. Historically used for making tools due to its hardness and sharp fracture edges.

Geological Facts

Jasper is an opaque variety of chalcedony. The name 'jasper' means 'spotted or speckled stone,' derived via Old French and Latin from the Greek 'iaspis'. It has been a popular gemstone since antiquity, mentioned in numerous historical texts including the Bible.

Field Identification & Locations

Identify in the field by its opacity (unlike translucent agate), extreme hardness (it will scratch glass), and its characteristic smooth, rounded surface when found in water. It often displays distinct color bands or stripes from iron rich impurities.

Identified on: 4/20/2026

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