Do you think having multiple, competing, currencies would be a good idea? What are the downsides?

The answer is filtering so c

1)    "way light reflects from a mineral" —  luster ;

2)  "way a mineral breaks under stress " — cleavage ;

3)  "reveals true, natural color of a mineral
                (note: when in powdered form) — streak ;

4)  "least reliable property for identification" — color ;

5)    "measured using the mohs scale" —  hardness .

The correct answer is a (edgenuity 2k17)