pitchstone
/ˈpɪtʃstəʊn/Definitions
1. noun
A type of volcanic glass, typically pale in color, that is often used in jewelry.
“The geologist studied the formation of the pitchstone in the ancient volcanic rock.”
2. noun
A type of dark-colored stone used in the manufacture of phonograph records.
“The record factory used pitchstone to create high-quality vinyl records.”