Shale
Rock
About it
Fine-grained rock of clay and silt that splits into thin, flat layers and feels smooth, not gritty. The Burgess Shale of British Columbia holds famous fossils, and black shales are a source of oil and gas.
- Type
- Rock (sedimentary)
- Group
- Sedimentary (clastic)
- Specific gravity
- 2–2.7
- Lustre
- dull, earthy
- Colours
- grey, black, red, brown, green
- Transparency
- opaque
- Cleavage and fracture
- splits into thin layers along bedding (fissile)
Typical values: real specimens vary. For more, see mindat.org.