the 12 might very well indicate 12ct...the *5 would then indicate 0.5 or half...i.e. half 24ct (pure gold), which of course is 12!
12ct is pretty rare, so it would be well worth further investigation.
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Researching British Hallmarks by: Anonymous
Hi Donna, thanks for writing in. Unless you can read the date letter, and determine if the letter is a "K" or a "H" you will not be able to determine a date. You may need to use a Jewelers Loupe for this.
Concerning the digits, "12" it may be the gold standard mark.
