www.925-1000.com

НЕРЖ.СТ means stainless ( НЕРЖ-Nerzaveuzaa) , steel (СТ- Stal') . Not Stalin.
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Maybe it is Previshenie (over) Normi (standard) - (PN) that means higher percentage of gold
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Hi!
I think, that "IIGAT" is for "Second (II) Quality (GATUNEK)"

the mark of manufacturer 9KXK: 9 for 1969 and the KXK for Кубачинский Художественный Комбинат, "Kubachensky Khudozestwenny Kombinat" (Kubachy Artistic Handicraft Factory) Purity mark 875 is of Moskow assay ofice, which provides this service for the Kubachy ...