The question was
what mineral falls at the softest end of the Mohs scratch hardness scale? Talc (is the answer).
It has a measure of 1 on that scale and can be scratched with a
fingernail.
The question (&
answer) are taken from p. 19 of Gemstones of the World by Walter
Schumann. The book was published by
Sterling Publishing Co. in 1998.
