This is a small jar of anthracite coal, rice sort, from Pennsylvania.
There is approximately 0.56 pound (255 grams) of coal inside the jar. The total weight of the coal and jar is approximately 0.66 pound (298 grams). There will be some slight variation from jar to jar.
Anthracite coal, or hard coal, has the highest carbon content, the greatest hardness, and the fewest impurities.
This is "rice coal". Rice is a measurement of size, not content. The pieces of rice coal are 3/16" to 3/8" (4.8 to 9.5 mm).