Turun Hopean used the responsibility mark OMN from 1960 to 1962, when the company was known as Kultasepät Miettinen Nurmi. The OMN mark came from words Olavi Mauno Nurmi. The TH-style symbol characterised by Turun Hopean began use in 1962. The final mark in the series is that of the product designer.
S = Pentti Sarpaneva (1967–1985)
L = Jorma Laine (1971-)
V = Juhani Vuorisalmi (1977-)
UNIDENTIFIED
The following marks have also been used:
0, 1, 4, 6, 7, 8, T, Z
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