How to Identify Lab Grown Rubies

Look at the stone with the naked eye for nicks, dings, scratches or gouges on the stone surface and along the edges of the facets. Ruby has a gemological hardness rating of 9, making it one of the hardest stones in nature next to the diamond. Synthetic stones, regardless of how they are made, cannot match the hardness of a natural ruby stone. Nicks or other marks identify a synthetic ruby.

Hold the ruby in front of a non-florescent white light source and look at the stone through a jeweler's loupe to detect air bubbles. The magnification of the loupe reveals any air pockets or bubbles in the stone, which indicate a synthetic stone.

Examine the stone through the loupe for uniform striation, or thin parallel lines, on or in the stone. Such markings do not occur in nature and indicate a synthetic stone.

Touch the lens of a dichroscope to the stone. Do this while the stone is in front of the white light source. Look through the eyepiece at the stone while slowly rotating the dicroscope with fingers, as with a kaleidoscope.

Note the colors presented in the two color squares inside the dicroscope. Rubies are dichroic ("di" meaning "two" and "chroic" meaning "color") because natural ruby crystal causes light passing through it to bend in two different directions. The dichroscope separates the light frequencies inside the stone into two discernible colors and shows them as two side-by-side color squares. When looking at a natural ruby with a dicroscope, the color squares always must be blue-red and orange-red regardless of where the dicroscope is in its rotation. Any other color combination indicates a stone other than ruby, and glass cannot produce dichroic color frequencies. Thus, lab-created rubies don't present at all through a dicroscope.