sedimentary
Red Jasper
Jasper (Silicon Dioxide with Iron Oxide inclusions), SiO2 + Fe2O3
Hardness: 6.5–7 on Mohs scale. Color: Opaque brick red to brownish-red. Luster: Vitreous to dull. Crystal Structure: Hexagonal (microcrystalline/cryptocrystalline). Cleavage: None (conchoidal fracture). Specific Gravity: 2.58–2.91.
- Hardness
- 6
- Color
- Opaque brick red to brownish-red
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6.5–7 on Mohs scale. Color: Opaque brick red to brownish-red. Luster: Vitreous to dull. Crystal Structure: Hexagonal (microcrystalline/cryptocrystalline). Cleavage: None (conchoidal fracture). Specific Gravity: 2.58–2.91.
Formation & geological history
Formed through the infiltration of silica-rich water into volcanic ash or fine-grained sediments, often during the Proterozoic or Paleozoic eras. The red color is derived from high concentrations of iron oxide (hematite) during the mineralization process.
Uses & applications
Commonly used in jewelry as cabochons or beads, ornamental sculptures, and as a popular stone for tumbling and collecting. In ancient times, it was used for seals and amulets.
Geological facts
Red Jasper was known as the 'rain-bringer' in Native American cultures and was frequently used for carving bow guards. It is technically an impure variety of silica, containing up to 20% foreign materials which give it its distinctive opacity and color.
Field identification & locations
Identify in the field by its deep red color, characteristic waxy to dull luster, and its inability to be scratched by a steel knife. It is common in riverbeds and desert environments in regions like India, Brazil, Madagascar, and the Southwestern United States.
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