Rock Identifier
Red Jasper (Silicon dioxide with hematite impurities (SiO2 + Fe2O3)) — mineral
mineral

Red Jasper

Silicon dioxide with hematite impurities (SiO2 + Fe2O3)

Hardness: 6.5-7 (Mohs scale); Color: Brick red to brownish-red; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91.

Hardness
6
Color
Brick red to brownish-red
Luster
Vitreous to dull
Identified More mineral

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Brick red to brownish-red; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91.

Formation & geological history

Formed when silica-rich fluids permeate volcanic rocks or sedimentary layers, picking up iron oxides (hematite) which provide the red color. Often associated with Precambrian banded iron formations.

Uses & applications

Used primarily as a decorative gemstone, in cabochons for jewelry, ornamental carvings, and aquarium decor. Historically used for making tools due to its conchoidal fracture.

Geological facts

Jasper is an opaque variety of chalcedony. In antiquity, it was often referred to as a 'rain-bringer' and was mentioned in the Bible as one of the stones in the High Priest's Breastplate.

Field identification & locations

Identify by its deep red color, opacity (light does not pass through even thin edges), and its ability to scratch glass. It is commonly found in India, Brazil, USA, and South Africa.