Testing the standard fineness of precious metals

Gold is easiest to test with testing acids. Acids are available for 8 carat, 14 carat and 18 carat. Who doesnīt want to buy all three acids, takes the one for 14 carat.

You have to make sure that the jewelry is not covered with galvanic-plating. For example it may be gold plated or covered with rhodium. If possible work on the surface with a 240 granulated sandpaper. Then put the acid on the same place.

For example: You put an 14 carat acid on the gold surface. The acid stays clear, and thereīs no changing of colour. That means, that you have 14 carat or higher quality gold. If the colour changes and you get a very, very light brown discoloration, you probably also have an 14 carat quality gold, but not a higher one.

If there is a dark brown discoloration, itīs presumably an 8 carat gold. A brown discoloration always suggests a gold content with a lower caratnumber.

If thereīs a green discoloration, the material is false.

For the silverdefinition you can also use the 14 carat gold-acid. Silver gets coloured grey.

You can see the testing of standard fineness on precious metals in Tutorial No.2 in an special filmclip - Just click "HERE"