sedimentary (microcrystalline quartz)

Red Jasper (River Pebble)

Silicon Dioxide (SiO2) with hematite impurities

Hardness: 6.5-7 (Mohs scale); Color: Brick red to deep maroon; Luster: Dull to waxy when unpolished; Crystal structure: Trigonal (microcrystalline/cryptocrystalline); Cleavage: None/Conchoidal fracture; Specific gravity: 2.58-2.91

Hardness: 6
Color: Brick red to deep maroon
Luster: Dull to waxy when unpolished

Identified March 7, 2026More sedimentary (microcrystalline quartz) →

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Physical properties

Formation & geological history

Formed when fine-grained silica (found in volcanic flows or sea floors) is replaced or saturated with iron oxides. This rounded specimen was likely weathered and smoothed by water transport in a river or coastal environment. Common in Precambrian and Phanerozoic deposits.

Uses & applications

Used primarily for lapidary work, jewelry (cabochons), interior decoration, and as a popular stone for tumbling. In ancient times, it was used for cylindrical seals and amulets.

Geological facts

Jasper is an opaque variety of chalcedony. The red color is caused by the inclusion of iron (Hematite). In ancient Egypt, red jasper was associated with the 'Blood of Isis' and used as a protective charm.

Field identification & locations

Identify by its solid red color, inability to be scratched by a steel knife, and smooth/rounded texture if found in water. Commonly found in riverbeds, gravity deposits, and shorelines worldwide, including the US (Oregon, Idaho), India, and Brazil.

Other sedimentary (microcrystalline quartz) specimens

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K2 Jasper (K2 Granite)

Azurite in Granite (Biotite Granite with Azurite inclusions)

igneous

Dalmatian Stone (commonly called Dalmatian Jasper)

Peralkaline Rock (mixed Feldspar, Quartz, and Arfvedsonite)

igneous

Dalmatian Jasper

Peralkaline Quartz-feldspathic Rock (Arfvedsonite-bearing)

igneous

Black Jasper (Black Onyx substitute)

Silicon Dioxide (SiO2) with carbonaceous impurities

sedimentary (microcrystalline quartz)

Yellow Jasper

Chalcedony (Silicon Dioxide, SiO2)

sedimentary (microcrystalline quartz)

Jasper

Jasper (Silicon Dioxide, SiO2)

sedimentary (microcrystalline quartz)