How can someone determine the Lithology of of rock samples without calculating the density of the sample?

I have 3 different samples i dont know what each sample is but i know that they r either sandstones, limestones or dolomites

Look at the properties of the rock, like composition. Get a hand lens and look at what minerals are in the rock, look at the grain/clast size and from there you can determine the formation of it and then determine what rock it is. Look to see if the grains are foliated or interlocking and the texture.