You can determine the rough purity of gold with some home tests.
If you are a gold buyer or seller, you need to be able to determine the rough purity of gold. To do so, you will need a touchstone, testing solution and gold test needles, along with a few of the skills needed to use the equipment and evaluate the results of your research.
Instructions
1. Check for identification marks. Look at the gold item for some identification marks like 10k, 14k, 18k and 24k.
2. Pick up the test needle and touchstone. To test an 18k gold item, you will need an 18k test needle.
3. Scratch the touchstone with test needle. It should be a firm scratch, but should not cross the entire surface.
4. Scratch the touchstone with the gold item. Make another scratch next to the one you made before with the needle. So you will have two scratches located side-by-side on the surface of touchstone.
5. Use the acid solution that is calibrated to 18k if your test needle is of 18k. Use that of 24k for a 24k test needle. Drop one or two drops of the solution on the scratches you made before.
6. Analyze your results. The color of the two scratches will be the same if your gold is pure. If the colors do not match, then repeat the process with different needles and solutions.
