Feb 27, 2017. 1  Tonight, Casey Affleck took home the Academy Award for Best Actor for his role in Manchester by the Sea. While this might be a reason for celebration for the new Oscar-winner, not everyone was so eager to join in with the applause.
Bituminous coal is a sedimentary rock. Anthracite coal is considered a metamorphic rock.
Lignite is considered to be immature coal at this stage of development because it is still somewhat light in color and it remains soft. As time passes, lignite increases in maturity by becoming darker and harder and is then classified as sub-bituminous coal. As this process of burial and alteration continues, more chemical and physical changes occur and a the coal is classified as bituminous. At this point the coal is dark and hard.