What properties are used to identify minerals and gems?

There are many properties to identify minerals and gems.
Almost all, if not all are physical properties of the mineral/gem.

Where so of the ways they are distinguished:
1. Color
2. Luster (How shiny it is)
3. Streak (What color it leaves behind when rubbed on usually a white tile)
4. Hardness (Measured by the Mohs Hardness Scale)

There are more, but those are the main 4.

Hope this helps!