How to Do a Gold-Plated Test

Gold is often mixed with other metals.

Natural gold is a very soft, malleable metal. Other metals are typically added, or "plated" to the gold to make it stronger and thicker, such as silver and zinc. The level of gold in jewelry is measured by the karat value. Twenty-four-karat gold is nearly 100 percent gold, while 18 karat is 75 percent, 14 karat is 60 percent, 12 karat is 50 percent and 10 karat is 40 percent. The remaining material is typically comprised of other metals and minerals. An acid test is a good method to determine the amount of plating used in gold jewelry or other gold items.

Things You'll Need

• Gold material
• Gold acid test kit

Instructions

1. Scratch the gold item on the black testing stone provided with the kit. Continue scratching the stone until a solid line of color is visible.

2. Scratch the test stone with one of the gold scratch needles provided with the kit next to the scratch made by the gold material.

3. Use the 10-karat gold acid test and place a drop onto the scratch from the gold material. Place a drop on the scratch from the gold scratch needle for comparison. If the scratch from the gold material dissolves, it is less than 10-karat gold and the plating content is high.

4. Repeat steps 1 through 3 and use the 14-karat gold acid. If the scratch dissolves, the material is approximately 60 percent gold with other plating.

5. If the acid test kit does not provide an acid test for 12-karat gold and the scratch did not dissolve using the 18-karat test, use the 14-karat gold acid test. If the scratch dissolves slowly and leaves some color on the test stone, it is probably less than 14-karat gold but more than 10 karat gold, most likely in the 12-karat gold range. This indicates a moderate level of gold plating on the item.

6. Repeat steps 1 through 4 and use the 18-karat gold acid to test the scratches. If the scratch dissolves, the material is 75 percent gold with minimal plating. If the scratch dissolves slowly and leaves color on the stone but does not dissolve when also tested with the 14-karat acid test, it is probably approximately two karats below the 18-karat test acid level.

Tips & Warnings

• Use caution when performing an acid test, as acid can burn skin, eyes, clothing and other material. Protective clothing and gloves should be worn.

References

• Argonne National Laboratory: Test for Gold
• Handy Harman Canada: Gold
• Shor International Corporation: Instructions for Scratch-Testing Gold

Resources

• Read this Article in Spanish