sedimentary
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Hardness: 6.5-7 (Mohs); Color: Brick red, orange, and yellow; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Specific gravity: 2.58-2.91
- Hardness
- 6
- Color
- Brick red, orange, and yellow
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6.5-7 (Mohs); Color: Brick red, orange, and yellow; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Specific gravity: 2.58-2.91
Formation & geological history
Commonly formed when silica-rich fluids permeate volcanic ash or sedimentary rocks, often during the Proterozoic or Paleozoic eras as part of banded iron formations.
Uses & applications
Used primarily for lapidary work, decorative cabochons, jewelry, seal stones, and as an ornamental garden stone.
Geological facts
Jasper has been used as a gemstone since antiquity and is mentioned in various historical texts such as the Bible. The red color is specifically due to high concentrations of iron oxide (hematite).
Field identification & locations
Look for a smooth, opaque, waxy finish on pebbles. Common in riverbeds and coastal areas of India, Brazil, Australia, and the USA. It will not scratch with a pocketknife.
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