sedimentary
Red Jasper
Silicon dioxide (SiO2) with iron inclusions
Hardness: 6.5-7 (Mohs scale); Color: Brick red to brownish red due to iron(III) oxide; Luster: Vitreous to dull; Crystal system: Trigonal/Microcrystalline; Cleavage: None; Fracture: Conchoidal.
- Hardness
- 6
- Color
- Brick red to brownish red due to iron(III) oxide
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Brick red to brownish red due to iron(III) oxide; Luster: Vitreous to dull; Crystal system: Trigonal/Microcrystalline; Cleavage: None; Fracture: Conchoidal.
Formation & geological history
Forms from the accumulation of microcrystalline quartz or chalcedony in hydrothermal veins or sedimentary deposits, often enriched with high iron oxide content which provides the red coloration.
Uses & applications
Primarily used for decorative purposes, lapidary art, jewelry (cabochons and beads), and as a collector's gemstone. Historically used as a material for seals and tools.
Geological facts
Jasper was a favorite gem in the ancient world, mentioned in biblical texts and used consistently across Greek, Roman, and Mesopotamian cultures for protective amulets.
Field identification & locations
Identify by its solid red color, inability to be scratched by a steel blade, and smooth, curved (conchoidal) fracture lines. Commonly found in riverbeds, glacial deposits, and gravel pits globally.
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