The mark

The Indian karat mark, in the modern BIS hallmarking system, is expressed as a three-digit fineness number (916, 750, 585) rather than as a karat figure (22K, 18K, 14K). The fineness number indicates the parts per thousand of pure gold by weight: 916 indicates 91.6 percent pure gold (22 karat equivalent), 750 indicates 75.0 percent pure gold (18 karat equivalent), and 585 indicates 58.5 percent pure gold (14 karat equivalent).

The fineness convention

The fineness convention, expressing gold purity as parts per thousand rather than as a karat figure, is the international standard adopted by the BIS hallmarking system in alignment with European and other national hallmarking practices. The advantage of the fineness convention is precise representation of intermediate purities and consistency across international trade. The 22 karat figure represents an idealised value; the actual fineness specification of 916 corresponds to the precise nominal purity of the BIS standard.

Reading the mark

The Indian karat mark appears as part of the four-element BIS hallmark: the BIS standards mark (triangular logo), the fineness number (916, 750 or 585), the assay centre identification mark, and the unique HUID code. The fineness number is typically the most visually prominent of the four elements after the BIS triangle.

The two-system context

Indian consumers and the trade still use the karat designation (22K, 18K, 14K) in conversation and marketing, with the fineness number serving as the formal hallmarking representation. The two systems coexist: a piece marked 916 is conventionally described in retail as 22 karat, with both descriptions being equivalent. The transition to fineness-only marking has not eliminated the karat usage from everyday trade language.