are you talking about a living plant or dried cure bud? if its living then the bud, leaf, and plant structure will help you easily identify the type. if you are refering to dried bud you are gonna have to smoke that shit!!! that might help, also i forget where i heard this but one is slightly more dense than the other. I dont know how to go about finding the volume and weight of the bud in a dealing situation but i hope that gives you a start