sedimentary
Yellow Jasper / Chert
Jasper (Silica/Quartz) - SiO2
Hardness: 6.5-7 (Mohs scale); Color: Yellow-brown, mustard, ochre; Luster: Waxy to dull; Crystal structure: Trigonal (Microcrystalline); Cleavage: None (Conchoidal fracture); Specific gravity: 2.58-2.91
- Hardness
- 6
- Color
- Yellow-brown, mustard, ochre
- Luster
- Waxy to dull
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Yellow-brown, mustard, ochre; Luster: Waxy to dull; Crystal structure: Trigonal (Microcrystalline); Cleavage: None (Conchoidal fracture); Specific gravity: 2.58-2.91
Formation & geological history
Formed from the deposition of silica in sedimentary environments or through the replacement of organic materials. The yellow color is typically due to the inclusion of iron oxides (Goethite). Geological age varies widely from Precambrian to Cenozoic.
Uses & applications
Used in gemstone carvings, jewelry (cabochons), or as decoration. Historically used for making tools due to its sharp conchoidal fracture.
Geological facts
Jasper is an opaque variety of chalcedony. Yellow jasper is often called 'Yellow King Jasper' and was historically used as a protective stone by travelers during the Middle Ages.
Field identification & locations
Identify in the field by its hardness (cannot be scratched by a steel knife), smooth waxy feel when polished by water, and shell-like fracture pattern. Commonly found in riverbeds, beaches, and desert environments worldwide.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone Grain
Clastic Sedimentary Rock Grain (SiO2 dominated)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Sandstone
Arenite
sedimentary