Testing the purity of gold is simple.
For thousands of years, gold (which is relatively rare in comparison with other minerals) has been highly valued. Although dense, gold is rather soft, comparable to the texture of a penny. This malleability has made gold popular for shaping into decorative ornaments. The purity of gold is measured in karats, with 24 karats denoting pure gold. The color of pure gold is a bright yellow. However, mixing gold with other metals like nickel, iron, or silver can change its color to silverish-white or orange-red.
Instructions
Various Tests
1. Put a magnet near your gold for this simple test. Magnets attract other metals in the gold. If the magnet is attracted to the gold, then the gold is not pure.
2. Rub your gold against unglazed porclean tile. If there is a black mark left then it is not pure. The black mark means there is pyrite present. Pure gold would leave behind a bright yellow mark.
3. Scratch a piece of glass with your gold. Gold measures between 2.5 and a 3 on the Mohs scale, named after Frederich Mohs, a German mineralogist. The scale measures the hardness of minerals on a scale from one to 10, with 10 being the hardest. Gold measures between 2.5 and 3, while most glass is between 5.5 and 6.5. You can also try a penny, which is around 3 on the scale or platinum, between 4 and 4.5. If you try to scratch the gold against another substance that is harder and the gold scratches that substance, then it is not pure gold.
4. Drop some sulfuric acid on the gold. When a drop of sulfuric acid is applied to pure gold, it will not dissolve. If it begins to dissolve, the gold may be mixed with other minerals.
5. Take your gold to a jeweler. They have proven ways to examine gold and can tell you how many karats (or how pure) your gold is. If you don't trust the first jeweler, take your gold to multiple stores to be sure.
