Emerald is one of the most famous and beautiful gemstones. It is appreciated for its deep rich green color. The mysterious depth of emeralds has been known to people since ancient times. These gems are credited with magical and healing properties. And there are much more people who want to buy natural emerald than the stones themselves. Therefore, the number of counterfeits is not surprising.
- - strong magnifier;
- - refractometer;
- - color filter.
Place the stone on a white piece of paper and evaluate its color. All emeralds are colored in different shades of green. If there are yellowish tones in the color, most likely in front of you is a green garnet or peridot. The green color of emeralds has a bluish tint.
Turn the stone under bright light. Pay attention to the variance. This word gemologists call flashes or sparks of light formed due to various inclusions. Emeralds have a low dispersion level, so natural stones give little "fire". If the gem sparkles and shimmers, most likely cubic zirconia is in front of you.
Check the stone with a refractometer. The refractive index of emeralds is approximately 1.58.
The green color, for which emeralds are so prized, arises due to the large presence of chromium in the mineral. Therefore, emeralds appear brown or red under the color filter. But the filter will not allow you to distinguish a natural emerald from an artificial one.
Green fluorite has exactly the same shade under the filter, but it is much softer than emerald and is easily scratched even by glass. Fluorite under ultraviolet rays fluoresces with violet light. In emeralds, both luminescence and fluorescence are rare and usually have a red or green color.
Examine the edges of the stone carefully. Very common imitations of emeralds, called "doublet" or "triplet" It is like a sandwich of glass, green epoxy resin and a thin cut of low quality emerald. When viewed from the side, the fake is clearly visible.
Pay attention to the "worn out" of the edges. The hardness on the Mohs scale of emeralds is quite high, so they remain faceted for a long time. Glass imitations wear out quickly. This is clearly visible under a strong magnifying glass.
Natural emeralds always contain foreign inclusions. They are clearly visible under a magnifying glass or microscope. Therefore, emeralds appear slightly cloudy. All these cracks, bubbles and feathers do not spoil the minerals. Jewelers call this effect the term "Jardin" (from the French for "garden"). Such defects are almost never found in grown stones.