Read the stamp
375 gold stamp
A 375 gold stamp can have CT wording on British and Commonwealth jewelry; CT names the metal’s carat grade, not a gemstone weight.
375, 9K and neighbouring stamps
375 and 9CT are equivalent gold designations. CT is a carat abbreviation used on British and other Commonwealth jewelry; it describes the metal rather than a gemstone weight. Common combinations include 9K 375 and 375 ITALY. Look inside a ring shank or on a chain clasp or end tag.
What to check next
Keep suffixes attached to the number: 9K GF describes a gold-filled layer and 9K GP a plated layer. A plain 375 fineness mark describes the gold alloy. On a chain, inspect the links as well as the clasp because a replacement clasp can carry its own stamp.