sedimentary

Jasper

Silicon dioxide (SiO2) with impurities

Hardness: 6.5-7 (Mohs); Color: Red, brown, and ochre due to iron oxides; Luster: Dull to vitreous when polished; Crystal Structure: Microcrystalline/Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91

Hardness: 6
Color: Red, brown, and ochre due to iron oxides
Luster: Dull to vitreous when polished

Identified April 4, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the deposition of silica from volcanic ash or hydrothermal solutions into cracks or voids. It is often found in sedimentary rocks that have undergone significant pressure and chemical exchange. Geological age varies from Precambrian to more recent eras.

Uses & applications

Used primarily as a gemstone for jewelry, in lapidary arts for cabochons and carvings, and as decorative stone in mosaics and ornaments.

Geological facts

Jasper has been used by ancient civilizations for seal stones and amulets for thousands of years. It is mentioned in several historic texts and was believed by the ancients to have protective and grounding properties.

Field identification & locations

Identify in the field by its opaque nature (unlike agate), its hardness (will scratch glass), and its characteristic smooth, waxy feel when weathered. Commonly found in riverbeds, desert landscapes, and volcanic regions globally.