Measure of gold purity (5)

I believe the answer is:

carat

(Other definitions for carat that I've seen before include "weight of rocks" , "Unit of gem measurement" , "Gemstone weight unit" , "Unit of measurement for the proportion of gold in an alloy" , "Precious stone weight" .)

I've seen this clue in The Times and The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.