sedimentary
Red Jasper
Silicon dioxide (SiO2) with iron oxide (Hematite) inclusions
Hardness: 6.5-7 (Mohs scale); Color: Brick red to brownish red; Luster: Dull to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91
- Hardness
- 6
- Color
- Brick red to brownish red
- Luster
- Dull to waxy
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Brick red to brownish red; Luster: Dull to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91
Formation & geological history
Formed from the deposition of silica-rich volcanic ash or fine sediment. The red color is derived from high iron content (up to 20%). Over millions of years, heat and pressure transform the sediment into dense, opaque microcrystalline quartz.
Uses & applications
Extensively used for cabochons in jewelry, garden landscaping, or as tumbled stones for decoration. Historically used for making tools and seals due to its hardness and durability.
Geological facts
Ancient Egyptians often wore red jasper amulets to symbolize the blood of Isis and provide protection. It is a variety of chalcedony that is specifically distinguished by its opacity.
Field identification & locations
Identify in the field by its deep red color, characteristic smooth 'waxy' feel when wet, and lack of transparency (it will not let light through even at thin edges). Commonly found in riverbeds and on beaches such as those in the Pacific Northwest or Southwestern USA.
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