1. The problem statement, all variables and given/known data I saw a division in a rock identification chart given to me by a lecturer.It says, Rock made of particle or crystals.I was wondering wat is different in both of these two and how to distinguish between them and identify them 2. Relevant equations 3. The attempt at a solution As for my knowledge, particle is an individual piece which integrates with others into a rock and crystal is a proper arrangement structural elements which is spread around forming rock.How do we see and distinguish between them.The identification is visual and things which could be used was an acid only to check whether it fizess with it or not. Help appreciated.