In the past, one of the most common techniques to test if a diamond was real or synthetic was to scratch the gem against glass- if the glass is scraped or scratched, the diamond’s real. But this method is not foolproof, as some faux diamonds can also scratch glass.
How to tell if a diamond is real or fake.?
How to Tell if a Diamond is Real or Fake
Can cubic zirconia scratch glass?
According to Abazias Diamonds, cubic zirconia does not scratch glass and in fact can be scratched by glass. A real diamond, on the other hand, can scratch glass.
Reference: qacollections.com/Will-a-cubic-zirconia-scratch-glass
How can you tell if something’s real gold?
To perform this test to check if gold is real, make a light, tiny scratch on the item using a small nail file. Choose a spot that is not noticeable if possible. Use a dropper to apply a small drop of nitric acid to the scratch. If there is no reaction, then the piece is probably made from real gold.
Can You Scratch A Diamond With Sandpaper?