Don't assume that because a piece of gold jewelry is stamped with 10K, 14K, 18K, 22K or 24K that the metal that you are looking at is the real thing. Under-carating, when metal is falsely marketed as a higher carat than it actually is, is a real problem in jewelry selling. Carat refers to the percentage of actual gold in the piece--24 carat gold has the highest concentration of gold, while 10 carat gold has the lowest concentration of gold and is the lowest concentration of gold that can still be sold under the label of gold in the U.S..
Observe the Surface of your Necklace
There shouldn't be any discolorations due to rust or tarnish. Such discolorations indicate a high content of non-gold metal in the necklace. Gold can be either white, like silver or platinum, or yellow, so the base color should not be a primary indicator. Gold with a reddish hue contains copper.
Imitate the pirate's test for gold by biting the gold in order to test its hardness. Gold is a relatively soft metal, especially when compared to other metals like nickel or copper. If your teeth leave a small indent, then the necklace is gold. Bite the gold in an inconspicuous part of the necklace.
Obtain a Gold Testing Kit
These kits use acid solutions to test samples of the metal in question. They come with a black stone on which the gold sample is scratched. It is the scratch, and not the piece itself, that is tested with the acid solutions. Gold testing kits come with multiple solutions, each for different concentrations of gold from 10K through pure 24K. Each solution is tested on the scratch successively until the right concentration is discovered.
Use a Quality Assurance Lab
Take the gold necklaceto a quality assurance lab if you are still concerned. They will test the necklace with an x-ray which will not damage to the piece.
Make sure that there is a warranty with your gold purchase that specifies that you can return it if a test determines that it is not real gold.
- ABC News: How Can you Tell if Your Gold Jewelry is Real?
- 8Trends.com: How to Recognize Fake Gold.
- NationalJewelersSupplies.com: Gold Acid Testing.