Gas bubbles only appear in natural emeralds near other inclusions of different shapes. If you see a swarm of bubbles alone, the gem is probably glass — but it could be a synthetic emerald.
The line between emerald and green beryl is blurred — two jewelers could disagree over the classification of a gem.
Strong dichroism (two very distinct colors) is a sign of a high quality emerald. [8] X Research source It is possible to get unusual results due to an internal reflection off a facet, due to properties of fluorescent light, or due to light reaching the viewing window without passing through the gemstone. [9] X Research source Use this along with other approaches, not as a single, definitive test.
Synthetic emeralds are much cheaper than natural emeralds, but not as cheap as most other synthetic gems. [11] X Research source $75 USD per carat is a ballpark figure for small, synthetic emeralds.
Look for a jeweler with accreditation from a national organization, such as the American Society of Appraisers or American Gem Society. A trade school degree in gemology is also a good sign. Avoid appraisers associated with a particular retailer, especially one that is trying to sell you the gemstone you want appraised. Fees vary greatly, and may be per-item, per-hour, or per-carat. Do not agree to an appraisal that charges a percentage of the emerald’s value. [12] X Research source
For a definitive test, continue on to the next step to get started using emerald filters. If you do not wish to purchase filters, skip down to the other tests. These do still require some tools, as synthetic emeralds are very difficult to identify by eye.
In some cases you will also need a jeweler’s loupe to examine the emerald up close. This is not necessary for most emeralds.
Place the emerald under a strong, incandescent light source on a flat, white background. (Fluorescent lights may alter results. ) Cover any attached metal or other stones with a tissue to prevent reflected colors. Hold the Chelsea filter close to your eye and note the color of the stone viewed through the filter, from about 10 inches (25 cm) away or a little closer. If the emerald looks red or pink through the Chelsea filter, continue to the next step to test it through the synthetic filter. If the emerald looks green through the Chelsea filter, skip down to the support filter step. If the emerald looks purplish-red, it is synthetic. Confirm borderline colors by looking through both other filters (synthetic and support) — if it looks greenish through both, it is synthetic. If it looks greenish through synthetic but reddish through support, it is natural.
Move the emerald several inches away from the light source, then view it through the synthetic filter. If it looks red or pink again, the gem is a flux-grown synthetic emerald. If it look greenish this time, it is a natural emerald, likely Colombian or Russian.
Move the emerald several inches away from the light source, then view through the support filter. If the emerald looks blue-green, lilac, or pink, it is a synthetic, hydrothermal emerald. If the emerald still looks greenish (but not blue-green), continue to the next step.
If it is clear and almost entirely free of inclusions, it is almost certainly a synthetic, hydrothermal emerald. If magnification reveals many small flaws (crystals, needles, wisps, and so on), the gemstone is a natural emerald that contains vanadium and/or iron, such as those mined in Zambia, Brazil, and India.
If you see a “pocket” in the gem that contains both gas bubbles and crystals, you have a natural emerald. This is called a “three phase inclusion. " Certain crystals only appear in natural emeralds: bamboo-like green actinolite fibers, mica flakes, or pyrite crystal cubes. [17] X Research source [18] X Research source [19] X Research source
Yellow, olive-green, or bright red fluorescence is a sure sign of a synthetic emerald. [20] X Research source [21] X Research source No fluorescence at all means the emerald is likely natural, but this is not guaranteed. There is one type of synthetic emerald without fluorescence. [22] X Research source Dull red or orange-red fluorescence could be natural or synthetic.
