How to separate diamond from its imitation?

Identifying any gemstone with naked eye or using 10x/20x loupe is very difficult. Even at certain level gemologists and traders fail to visually identify gemstone and take help of gemological instruments and labs. And when it comes in identifying diamond from its simulants (imitation) then the job gets more tougher.

Many gemstones imitates diamond. But there are mainly two (2) diamond-imitation which are heavily available in trade.

  1. Synthetic Cubic Zircon also known as "American Diamond", "C.Z." and some times "Zirconia".
  2. Synthetic Mossanite

There are some other diamond simulants which are not necessary to be known from the trade point of view but it's good to at least know their names.

  1. Synthetic Diamond i.e., lab-grown diamond
  2. Colorless Sapphire (also known as "white sapphire")
  3. Man-made Glass
  4. Strontium Titanate
  5. Yttrium Aluminium Garnet
  6. Gadolinium Gallium Garnet
  7. Synthetic Rutile
  8. Zircon

Separating diamond from its two (2) popularly known simulants:

Separating "Diamond" from "American Diamond" with read through effect test: RBC (round brilliant cut) diamond when placed table down on written matter (a line or a point) and viewed from above the girdle (pavilion facets) will not exhibit a read through effect while American diamond will exhibit a read through effect. Note: A perfectly cut "American diamond" may not exhibit read through effect at certain times so this is not a confirmatory test for separating diamond from American diamond.

Separating "Diamond" from "Synthetic Mossanite" with doubling effect test: When stone is viewed carefully through kite facets towards culet; the culet of "synthetic mossanite" will appear dobule, this appearance of culet is known as doubling effect. Doubling effect is not seen in diamond so this is a confirmatory test for separating diamond from synthetic mossanite. It should also be kept in mind that doubling test can be performed for inclusions and facet edges. That is, inclusions and facet edges of synthetic mossanite will also appear "double" when seen very carefully through kite facet using 10x/20x loupe.

And if stone is in white color than one should not bother much about "doubling test" because synthetic mossanite far or less does not comes in white color. Generally it comes in shades of yellow. But for confirmatory test one should apply all possible test to identify gemstones.

In case of studded ornaments and jewelries it is better to get it verified by reputed gemological lab.