sedimentary
Red Jasper (or Ironstone Pebble)
SiO2 (Quartz/Microcrystalline Chalcedony with Hematite inclusions)
Hardness: 6.5-7 on Mohs scale; Color: Deep reddish-brown, reddish-chocolate; Luster: Dull to waxy/sub-vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: None, conchoidal fracture.
- Hardness
- 6
- Color
- Deep reddish-brown, reddish-chocolate
- Luster
- Dull to waxy/sub-vitreous
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Physical properties
Hardness: 6.5-7 on Mohs scale; Color: Deep reddish-brown, reddish-chocolate; Luster: Dull to waxy/sub-vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: None, conchoidal fracture.
Formation & geological history
Formed via chemical precipitation of silica-rich fluids combined with iron oxide impurities, often smoothed and rounded through fluvial or weathering processes in stream beds and coastal gravel deposits.
Uses & applications
Used primarily for lapidary arts, ornamental carving, tumbling, decorative landscape gravel, and mineral collections.
Geological facts
Red jasper gets its rich reddish-brown color from fine particles of hematite (iron oxide) trapped within the cryptocrystalline quartz matrix.
Field identification & locations
Identified in the field by its hardness (scratches glass), smooth water-worn texture, dull to waxy finish, and opaque dark red-brown color. Frequently found in riverbeds, glacial till, and gravel pits.
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