i think so
Yes: not a good use for a diamond, but yes, a diamond will scratch a nail.
No
That would be Talc.
quartz
no it doesn't transmit disease unless if there is some virus in nail
Nail polish remover... or scratch it off... It does eventually fall off.
Paint it over a new nail polish and wipe it right away
No. Only another diamond can scratch a diamond.
Your nail is 2.5 so the rocks you can scratch are, Gypsum and Talc.
emerald is used for paper, glass, makeup, lipstick, fingernail polish, nail glue, and jewelry.
Most likely you would be testing to see if the mineral was harder or softer than the nail.