Crack is usually fairly soft and can break apart easily. Likely what you have is cocaine that has been heavily pressed into a brick before it was imported. Because the smugglers want it to be as small as possible, they use presses and vices to compact it to the point where you could almost build houses out of it. Generally once it has been through a few hands, someone will crush it up and cut it with something. So it may be some high-quality powder cocaine. Of course dealers know this as well and sometimes they will do the same press on highly cut cocaine because they know some cocaine users will get excited seeing it is "cut off of the brick".
I don't know clearly what will happen if you snort crack. I think much less of it is absorbed, if any because it is a water-insoluble freebase. You could take a tiny piece of it and try holding a lighter up to it, to singe it. Powder cocaine burns when it is heated and turns black while generally keeping its same shape whereas crack will usually make a light popping sound (supposedly where the name "crack" comes from; the crackling sound) while it melts. Far from a sure-fire test but it should be enough to tell I would think.