Silver weights - Troy oz, AV oz, grams or grains?

Youwilloftenseesilvercoins,roundsandbarsbeingsoldasweighingoneormore'ounces'.Butsometimesthesellerdoesn'tmentionwhichtypeof'ounce'theymean.Therearetwodifferenttypesofounce-theTroyounceandtheAvoirDupois(AV)ounce.PreciousmetalsareusuallyweighedinTroyounces.AVouncesarethetypethatareusedforeverythingelseandaretypefoundonyourkitchenscalesetc.The way to discover whether anitemisaTroyounceorAVounceistoaskfortheweightinGrams.1 Troy ounce = 31.103 grams 1 Avoir Dupoisounce = 28.349 gramsAs there's a difference of nearly 3 grams, modern kitchen scales are usually accurate enough.And then there are 'Grains', which the silver content issometimes stated as. There are 480 grains in a Troy ounce and 437.5grains in an AV ounce.Sometimes you will seesilverbarsthatareapparentlysilver and apparently weigh'oneounce'yethaveasilvercontentstated in grainsofalotlessthanyouwouldexpecttoseeinoneounce.1 ounce troy = 31.103 grams = 480 grains 1 ounce avoir dupois = 28.349 grams = 437.50 grains 1 gram = 15.43 grainsOther info:Sterling silver is 925partin1000parts pure silver,ie92.5%silver. .999 silver is 999 parts in 1000 parts pure silver, ie 99.9% silver..900 silver is 90% silver and is whatpre-1964USAsilvercoinsaremadeof.It is usually copper that makes up the other parts of the weight.