hallmark identification

Can anyone help? I have a silver napkin ring which is marked ‘84’ with a tree or leaf like stamp, and the initials T.H.
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This may be Russian silver. 84 zolotniki is a silver standard equivalent to .875. There is an unknown Russian silversmith with the initials TH and a very similar (if not identical) mark - see here. The mark next to the 84 may be the St Petersburg city mark. However it should also have an assayer’s mark so I am not confident about the attribution.

very helpful. many thanks.