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How do I know if my silverplate pieces are copper based? [Colorado] 

November 12, 2007 I am attempting to sell some silverplate pieces. I was asked a very unusual question today from a prospective buyer and unfortunately do not know the answer. The question was "Is any of your silver copper based?" I have no clue as to how to go about answering this gentleman. If anyone can tell me how to determine if any of my pieces are copper based, I would then like to know if this is a good feature or one of less interest to a buyer. Would copper based silverplate have more value? I truly would appreciate any answers I could get. JoAnne Kopetas Retired homemaker - Golden, Colorado, USA November 15, 2007 Better silverplate objects are copper or copper alloy based(brass,nickel silver).Low quality can be zinc alloy,tin alloy or even iron based(magnetic!).Copper /copper alloy based objects can be identified with nitric acid(put one drop on backside of object,after some time green coloured liqid must be formed/rinse well-sorry all simple tests are destructive-be careful,nitric acid is dangerous stuff).Hope it helps and good luck! Goran Budija - Zagreb, Croatia June 18, 2008 Hi, JoAnne. Eureka! Archimedes gave us a simple non-destructive test that will let you rule out that the silverplate could be made of certain materials. For example, if it's too heavy you know it's not zinc. Fill a plastic tub up to the brim, then lower the silverplate into it, catching the overflow in a larger tub. Compare the weight of the plate to the weight of the water it diplaced and you have its specific gravity. You can look up the specific gravity of copper and silver. Good luck. Regards, Ted Mooney, P.E.  finishing.com Brick, New Jersey

Dear Sir

Acid testing of a vessel for finding its base metal composition is a distructive method. A treatment with Nitric acid giving green colour or with Sulphuric acid giving a blue colour results in damaging the surface.

There are two properties on the basis of which the base metal can be identified. One is Electrical Conductivity and the other is density difference. As has been pointed By Mr Ted, Archimides principle exploits this density difference (Buyoncy) while a sensitive low resistance multimeter can be callibrated to find the type of metal in the base.

Manuj Kaushesh
- Delhi