It is not easy to tell the difference between rocks & minerals because there are so many kinds of them. It takes years of study to be able to accurately identify a mystery rock and even then rockhounds want to know where the specimen came from.
First of all I want you to have a look at some
specific vocabulary , essential if you are to describe them:
Color, luster, specific gravity, crystal form, cleavage, fracture, tenacity, hsrdness and transparency. You can also find a glossary of words and phrases and their definitions.
Maybe it is a good idea to have a complete
list of rocks and minerals toguether with their pictures, don't you thing? Click on this link and you will have all the minerals and roocks at hand.