sedimentary
Jasper
Jasper (Silicified microcrystalline quartz) - SiO2
Hardness: 6.5-7.0 (Mohs scale); Color: Red, brown, and tan mottled pattern (due to iron inclusions); Luster: Waxy to dull; Crystal structure: Hexagonal (Microcrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91
- Hardness
- 6
- Color
- Red, brown, and tan mottled pattern (due to iron inclusions)
- Luster
- Waxy to dull
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Physical properties
Hardness: 6.5-7.0 (Mohs scale); Color: Red, brown, and tan mottled pattern (due to iron inclusions); Luster: Waxy to dull; Crystal structure: Hexagonal (Microcrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91
Formation & geological history
Formed during the process of sedimentation and silica-rich hydrothermal activity. Often found in nodules, veins, or as replacements in sedimentary rocks and as impurities within volcanic deposits.
Uses & applications
Commonly used as a gemstone for jewelry (cabochons, beads), lapidary art, ornaments, and historically as a material for knapped tools like arrowheads.
Geological facts
Jasper was a favorite gem in the ancient world; its name can be traced back in Arabic, Persian, Greek, and Latin. It is also mentioned frequently in the Bible and is the birthstone for March in some traditions.
Field identification & locations
Identify by its opaque nature (unlike agate), smooth waxy feel, and characteristic conchoidal fracture (curved breakages). Look for it in riverbeds or coastal areas where silica-rich stones aggregate.
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