Imitation diamonds or fake diamonds are also known as faux diamonds. Or "simulant" as used by the industry insiders. It refers to materials, such as CZ, that look like another gem.
Glass, costume, cubic sirconia
You take it to a jeweler who can test the stone and verify that it is a diamond, or that it is imitation.
chromium
Ideally, you'd replace a diamond with another diamond. Or if you wanted the empty space to look like the diamond was still there, you could replace it with an imitation diamond. You can replace a diamond with almost any faceted stone.
rhinestone
Lure
Probably not, sorry. You may be able to find an imitation, though.
Real diamonds are formed from carbon; imitation diamonds are fabricated from a combination of materials.
So-called "copycat" offenses.
counterfeiting
Onomatopiea.
The imitation of natural sounds or words that sound like the sound they are supposed to make is called onomatopoeia.
canonic imitation is canonic imitation