Read the stamp
9ct gold hallmark
For a 9ct gold hallmark, the karat figure counts gold parts out of 24. 9K GF, 9K RGP and 9K HGE describe the gold layer over another metal.
9K and 375
The karat figure counts gold parts out of 24. 375 is the corresponding common fineness stamp. K, KT and CT are karat abbreviations. Rings often carry the stamp inside the band; chains may carry it on an end tab or clasp.
What to check next
9K GF, 9K RGP and 9K HGE describe the gold layer over another metal. Retain the suffix when reading a small stamp. Compare a worn K with the letters in any maker signature beside it; the maker initials and the purity mark answer separate questions.