How do you tell the difference between coals

I picked up a load of 'inexpensive' coal that the guy told me was anthracite. I loaded a bucket of coal I purchased myself from the coal dealer and a bucket of coal the coal I bought 'offline'. The known good stuff is black and glass like. The other stuff is black and not as glistening. I had read somewhere if you put a piece of anthracite in a vise and compress it it will shatter. And if you do the same to bituminous coal it will crush or mush.
Anyone tell me the difference or a way to help tell the difference? Is different mines anthracite noticeable different.
I believe both coals came from the same coal dealer as I picked it up less than 2 miles from the dealer. It was just purchased a dozen years or more apart.
Basically visually they look a little different so I'm concerned about burning it in my hopper feed hitzer 30-95.
Any help would be appreciated.

If the coal is bituminous, you will know quickly when you burn it. It will smoke and produce yellow flames. Throw a scoop on the fire to the side of the hopper and see what you think.

Thanks. Tried it a couple times. Getting consistent results. Flames look the same as they did with know 'correct' coal.