U. S. Mint Test for Gold and Silver.
Reading edition
The following is a test for determining whether coin is good or bad. Use the liquids as near the edge of suspected coin as possible, as that is the part most worn. A drop of the preparation will have no effect on genuine coin, while it can be plainly seen on the counterfeit. Coins should be scraped slightly before using:
TEST FOR GOLD.
Strong Nitric Acid (36°), 39 parts.
Muriatic Acid, 1 part.
Water, 20 parts.
TEST FOR SILVER.
24 grains Nitre of Silver.
30 drops Nitric Acid.
1 ounce Water.
The above tests should be taken in conjunction with Diameter, Thickness, and Weight, the tests used at the Mint.