it can scratch fluorite
Yes it can.
n
yes
The copper of the penny will rub off the file
steel file 6.5
No.because calcite is softer then feldspar
No. Diamond will scratch steel, however,
Diamond is the hardest naturally occurring mineral and can scratch all other minerals. Talc is the softest of minerals and cannot scratch any other mineral.
Diamonds are proven to scratch all minerals including itself.
Diamond is harder than steel: you can scratch steel with a diamond, but steel will not scratch a diamond.
Talc is supposed to be too fragile to cause a scratch on the majority of minerals.