We can distinguish among different  minerals by  hardness, colour and brightness.

    There are very hard minerals such as diamond and very soft ones such as talc. [ The classification of minerals by their hardness is called Mohs scale ].

    Also, there are minerals with characteristic colours such as malachite (green); and another with different colours such as beryl (green, blue, yellow,…).

There are very metallic bright minerals such as pyrite and however there are matt minerals too.

Diamond 

Malachite 

Pyrite