Jasperoid
Rock
About it
Dense, chert-like rock formed when hot silica-rich fluids replaced limestone or dolostone, often brown or red with iron oxide and quartz-lined cavities. A guide to gold, silver, and lead-zinc ores in Nevada and Utah.
- Type
- Rock (sedimentary)
- Group
- Sedimentary (silica replacement)
- Hardness (Mohs)
- 6.5–7
- Lustre
- dull, waxy
- Colours
- red, brown, grey, black, yellow
- Transparency
- opaque
- Cleavage and fracture
- none; conchoidal to splintery fracture
Typical values: real specimens vary. For more, see mindat.org.