Bituminous Coal
By Communications and Publishing
2013 (approx.)
Detailed Description
This sample is of bituminous coal, a middle rank coal (between subbituminous and anthracite) formed by additional pressure and heat on lignite. Usually has a high Btu value and may be referred to as "soft coal." Read more about USGS coal research here: https://www.usgs.gov/centers/cersc/science/us-coal-resources-and-reserves-assessment
Sources/Usage
Public Domain.
Public Domain