Anthracite
Rock
Also called Hard coal and Peacock coal
About it
Highest-rank coal: hard, fairly clean to handle, and shiny with a near-metallic lustre and conchoidal fracture; some shows a rainbow tarnish (peacock coal). Mined mainly in northeastern Pennsylvania.
- Type
- Rock (sedimentary)
- Group
- Sedimentary (organic)
- Specific gravity
- 1.3–1.8
- Streak
- black
- Lustre
- submetallic, vitreous (glassy)
- Colours
- black, steel black, iridescent tarnish
- Transparency
- opaque
- Cleavage and fracture
- none; conchoidal fracture
Typical values: real specimens vary. For more, see mindat.org.