It was a code letter representing the year of hallmarking of jewellery which is decided by BIS. The fifth component was the year of marking. Before revising the rules, effective from January 1, 2017, BIS hallmarking scheme had five components.
For gold jewellery hallmarked till 31 December, 2016 If you have bought the gold on or before 31 December, 2016, then there is an additional component that is hallmarked on the gold. This provides the names and addresses of the jewellers and date till which their licence with BIS is valid. The list offers names of both gold and silver jewellers that are certified and licensed by BIS. BIS on its website has put out a list of jewellers that are certified by the BIS. This mark can be of a BIS certified jeweller or jewellery manufacturer. Jeweller's identification mark The jewellery shop from where you are buying your gold jewellery will also put its identification mark.
Four signs of gold purity Image from BIS website 4. Click here to check the logo of the hallmarking centre on your jewellery. One can check if the hallmarking centre is licensed by BIS or not on their website. Only licensed laboratories of BIS can check the purity of gold. Assaying and hallmarking centre's mark/number The laboratory where your gold jewellery is assessed to check its purity is also required to put their logo on the jewellery. The fineness number and BIS hallmarked on the piece of jewellery indicates that BIS has certified it to be of the fineness level/purity that is embossed on it as part of the hallmark. Source: BIS Website As per the BIS website, an amendment is being issued to permit hallmarking of six caratages of gold/jewellery/artefacts viz.