The way that you can determine what type of mineral it is by checking their physical property and doing different methods to determine what type of mineral it is.
Do a scratch test on a ceramic plate to determine the streak color. Use Mohs hardness scale to determine the hardness. Try to identify its cleavage. Determine if the mineral has any kind of shine or luster. Find out if it is magnetic, if it has an odor. Color, alone, usually is not going to be enough to identify by.
It can be either they can have a negative or positive charge more specifically negatively charged molecule would called an anion and a positive one would be cation.
