This is a small jar of anthracite coal, pea sort, from Pennsylvania.
There is approximately 0.74 pound (335 grams) of coal inside the jar. 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 "pea coal". Pea is a measurement of size, not content. The standard sizing of pea coal is 9/16 to 13/16 inches (14.31 to 20.62 millimeters). Some random pieces measured 0.5 to 2 inches.