rotten stone
Rotten stone, sometimes spelled as rottenstone, also known as tripoli, is fine powdered porous rock used as a polishing abrasive for metalsmithing and in woodworking.
en-GB/ˈɹɒtn ˈstəʊn/
en-US/ˈɹɑtən ˈstoʊn/
Rotten stone, sometimes spelled as rottenstone, also known as tripoli, is fine powdered porous rock used as a polishing abrasive for metalsmithing and in woodworking.