
Undated
Ostby & Barton
The metal-standard text separates O and B, with an adjacent cross. This differs from a compact punctuated O.B. punch.
Read the stamp
For a 10K gold stamp, the karat figure counts gold parts out of 24. 10K GF, 10K RGP and 10K HGE describe the gold layer over another metal.
The karat figure counts gold parts out of 24. 417 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.
10K GF, 10K RGP and 10K 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.