Travel around Massachusetts to score a gemstone (10)
I believe the answer is:
tourmaline
'a gemstone' is the definition.
(I know that tourmaline is a type of transparent gem)
'travel around massachusetts to score' is the wordplay.
'travel around' becomes 'tour' (synonyms).
'massachusetts' becomes 'ma'.
'to score' becomes 'line' (lining is a kind of scoring).
'tour'+'ma'+'line'='TOURMALINE'
(Other definitions for tourmaline that I've seen before include "Beautiful grey or black mineral" , "Beautiful blackish mineral" .)