How can you tell if diamonds are real on a necklace?
One way to tell if your necklace contains real diamonds is to look for a stamp on the metal. If the necklace is made of gold or silver, it should have a stamp that indicates the purity of the metal. For example, a 14-karat gold necklace will be stamped "14K" or "14Kt". Silver jewelry is often stamped "925" to indicate that it is 92.5% pure silver.
If there is no stamp on the metal, you can try the fog test. breathe on the diamond and see if the fog clears quickly. If it does, then it's probably a real diamond. Another way to tell is by using a magnifying glass to look at the diamond. Real diamonds will have tiny imperfections on the surface, called "inclusions". Fake diamonds will usually be flawless.
You can also try the scratch test. Get a piece of glass and scratch it against the diamond. If the diamond is real, it should scratch the glass. If it doesn't, then it's probably a fake.
Finally, you can take the diamond to a jeweler and have it appraised. A professional will be able to tell you for sure whether or not your necklace contains real diamonds.