Gold is a rare metal commonly used in jewelry, currency and electronics. Its shiny yellow color made it popular throughout history for representing wealth. This popularity has also led to using substitutes in place of gold. A deductive test for gold involves attempting to dissolve a small piece of the item in acid. This test is called the acid test.
- Piece of jewelry or other gold item (test will destroy the item)
- Razor blade
- Rubber gloves (like those used for washing dishes)
- Safety goggles
- Hydrochloric acid
- Sulfuric acid
- 2 test tubes
Acids are caustic. They will cause chemical burns. Always use the appropriate personal protective equipment when handling acids. When adding one acid to another, tremendous heat can be produced. A few milliliters can heat a test tube hot enough to burn the skin.
Remove a small slice of the gold item with the razor blade. The slice only needs to be about the size of the tip of a pen.
Put on the rubber gloves and the safety goggles.
Fill one test tube 10 percent full with hydrochloric acid.
Fill the other test tube 10 percent full with sulfuric acid.
Very slowly add one test tube to the other. The test tube with the acid being added to it will get hot. Adding the acid slowly will prevent the test tube from getting too hot.
Carefully put the slice of gold into the test tube containing both acids. The acids will dissolve every metal except gold. If the slice fully dissolves, it does not contain any gold. If some of it remains behind, the piece does contain gold.
Things You'll Need
- gold coins image by cloud1971 from Fotolia.com