In the same vein as GoldPelican's Perth Mint bar style's thread, I thought I'd start one for Geomin. Information is very sketchy so will try to update as others post anything they know. History: An Australian mining (to be confirmed) and refinery who produced cast silver bars of various sizes in the late 1970's (and potentially early 80's). No rounds seem to have been produced. Gold cast bars were also produced but examples seem to be very rare (have only found a few examples to date). Both metric and troy ounce bars were produced and ranged in sizes from ~250grams to 250oz. Silver bars were either 999 fine or 999.9. So far all 250g bars I have seen are three nines, while all other bar sizes were four nines. It is less clear about the gold bars, but one was 995.8. Suspect most bars went to jewellers or industry and have been melted. Based on the serial numbers my rough guestimate is that they made around 6000 silver bars in total with a total weight of 4-5 tonnes. All bars have the Geomin hallmark a map of mainland Australia (without Tasmania) with GEOMIN written inside. All bars seem to have had serials numbers with the first letter indicating the product range. It is possible that many remaining bars are from the 1977 Christmas release which came in blue velvet presentation boxes. The 1977 Christmas range have two stamps Geomin and Bullion Sales Christmas 1977. Metric bars: 250g Serial numbers Gxxx 999 fine. Highest serial number found to date = G1158 G1244. This range does not have "Silver" stamped on them. 500g Serial numbers AGxxx 999.9 fine. 500g Serial numbers Sxx 999.9 fine. Dual stamp Geomin and Bullion Sales (represented by vertical BS) Christmas 1977 1000g Serial numbers AGxxx 999.9 fine 600g One site sponsor has told me they recently sold a 600g bar (with papers). No other details. Unknown if this was an overweight 500g. Troy ounce bars: 10oz Serial numbers Axxx 999.9 fine. This range does not have "Silver" stamped on them. 10oz Serial numbers Rxxx 999.9 fine. Does have "Silver" stamped on them. (Highest known serial to date = R168) 50oz Serial numbers Mxxx 999.9 fine, Axxx, and Bxxx confirmed - 50oz with serial number Bxxx with 99.98 fine confirmed 100 oz Serial numbers A,B,S and AGxxx confirmed unknown fineness (a bar with Mxxx serial was listed in the text on an auction, but no photo) 250oz Serial number ??? 999.9 fine (details from the listing but can't read from the photo) Gold: So far have only found: 2.51oz bar (cannot read the Serial number or fineness) 2.50oz bar = M73 (996.6 fineness) 5.03oz bar = A118 (997.2 fineness) 10.03oz bar = M285 (996.9 fineness) and a 1000.2 gram listed as gold being 995.8 fineness with serial number M991 (note that the M series was used for the silver 50oz). Edit As discovered in Post #20 it seems the serials are rough guides only with respect to weights with A, B, S and AG used for the 100oz weights. Have since read elsewhere that larger sizes were far more common than the <10oz sizes.