How do I Choose Investment Quality Rubies?
- 1). Compare clarity according the American Gemological Laboratory (AGL) clarity guide, and look for a Free of Inclusion (FI) rating. Clarity represents the internal perfection of the stone, and because investment-quality rubies require the highest clarity, you must look for flaws like internal cracks or chips within the stone. You can see some flaws with your unaided eyes, or you might need a jeweler's loupe to view the stone at 10x or 20x magnification.
- 2). Compare the tone of the ruby, and look for a medium tone score of 55 to 65. Too light a tone, and the ruby will appear diluted and washed out. Too dark, and the transparency suffers.
- 3). Compare the cut of the stone, and look for a AGL rating of "excellent." Cut represents the symmetry of the shape, the weight of the final stone, and the brilliance of the finish. Investment-grade rubies with excellent cut offer the best mix between the smoothest finish, the heaviest weight, and shape's precision.
- 4). Compare brilliance, and look for a minimum rating of 95 percent. Brilliance represents the precision of the cut, so that the maximum amount of light reflects back to the eye. Stones with lower than 50 or 70 percent brilliance lose light through the sides of the stone due to imperfections of the stone's angles.
- 5). Compare weights, and look for a minimum of one carat. "Carat" represents the weight of the stone derived from an ancient measures-and-weights system: 1 carob seed equals 200 milligrams. When it comes to investment-quality rubies, heavy stones hold value more consistently than lighter stones.
- 6). Examine the certification agency, and look for a score certified by the AGL. AGL has standardized, world-wide guidelines to describe stone quality. Stones graded without a standardized grading certificate might have undisclosed flaws or might not match third-party grading systems.
