Stone I removed from rough granite (6)
I believe the answer is:
garnet
'stone' is the definition.
(precious stone)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for garnet that I've seen before include "Glassy red, yellow or green gemstone" , "Deep red gemstone" , "Semi-precious stone of deep transparent red" , "Precious stone, usually red" , "Semi-precious stone of argent type" .)