calcite
nickel
A topaz
Calcium
Othoclase, apatite, fluorite, calcite, gypsum, and talc.
Topaz,Calcite Cooprarte
No, because calcite can be scratched off as easily as a copper penny. Would you like to have a diamond that breaks every time you do something active.
calcite
Gypsum
no
No
calcite
nickel
nickel
Topaz,Calcite Cooprarte
a penny has a hardness of 3 depending on what it is being scratched on.
A topaz