Can anyone direct me to a site or chart of the specific gravity of various coins? Preferably new MS coins, US or international. I have bouco tables of most metals and many alloys, but not of actual coins. Such charts can assist with identification and authenticity checks. Like what is the usual (typical) SG for a 2002 Jefferson nickel? Or stepping up, for a Au Kennedy proof? I make my own, but it is a slow process, and I do not have precise tools. thanks in advance Gary
I know where you can purchase a specific gravity kit: http://www.valleycoin.com/product_info.php?products_id=33034
If you already have a good balance, you can buy the SG adapter such as this http://www.mineralab.com/Scale.htm
SG for Jefferson nickel is 8.92 (CuNi) or 9.25 (war nickel) Silver Kennedy is 9.53 for 40% or 10.34 for 90% SG doesn't depend on size or denomination or condition, it depends on composition. So all of the 90% silver coins will be 10.34, all the 40% silver will be 9.53, all US CuNi clad coins are 8.92, all Zincolns are 7.17 etc. If you know what the composition of a coin is supposed to be you can calculate it's SG pretty closely, it is the sum of the percentages of each element times the SG for that element. For example a 1945 wheat cent is 95% copper and 5% zinc so the SG=(.95*8.96)+(.05*7.133) or 8.51+.357 = 8.86 The table I have says 8.83 The calculation helps for those world coins that you don't have a chart for. (Conversely if you don't know the precise composition the actual SG can help you determine what the composition could be.) If you really want a table of the specs for US coins, get a copy of the Coin World Almanac. You can pick up a used copy on Abebooks for under $5 including shipping. It will give you the table you want and a tremendous amount of other information. (Frankly everyone like to push the Redbook, but it is mostly a book full of meaningless prices and some good information. The CW Almanac doesn't have the meaningless prices but it does have a lot more info. I would MUCH rather give up my Redbook than I would my Almanac, and the Almanac is cheaper.)
