How to Tell Garnet From Ruby

By Ciele Edwards

If you like rich red rubies, it may in your best interest to learn how to tell a ruby apart from a garnet, a similarly colored yet much less expensive stone. Most jewelers can be counted on to be honest and provide you with a certificate of authenticity for your purchase. If you opt to purchase the gem online or from a private individual, however, you are more likely to fall victim to a scam. A ruby is a valuable stone, and ruby jewelry that can be passed down from generation to generation is well worth the added time and effort it takes to ensure authenticity.

A ruby is more valuable than a garnet.
Garnets are typically darker and more dense than rubies.

Step 1

Examine the coloring of the stone. A genuine ruby typically has a light red to medium red hue, whereas a garnet will be darker and have a burgundy or mahogany cast. In some cases, a ruby may also be mahogany, but it will always have a clarity that the dense, less refractive garnet does not.

Rubies are often found in exotic cuts.

Step 2

Check the cut of the stone. Rubies most frequently have exotic cuts, such as a cushion or pear cut. The larger the ruby, the more unlikely it is to find it in a standard cut. So if you are examining a two-carat stone in a brilliant cut, the stone may be a garnet.

Step 3

Hold the stone directly in front of your eye. The stone should be as close to your eye as possible without actually touching your eye.

Look for a rainbow pattern within the stone.

Step 4

Move the stone toward the light. Roll the stone around slowly between your fingers. Examine the light patterns that result within the stone. If you are holding a true ruby, you should see a rainbow pattern emerge in various shades of red and blue. A garnet, however, will display a rainbow pattern that contains greens and yellows.

Step 5

Look for double rainbows. A ruby is a doubly refractive stone, so it refracts light in a much different way than a garnet, which is singly refractive. If you are holding a ruby, the rainbow image you see will be blurred and appear almost as one rainbow on top of another. The rainbow image you see within a garnet will be much more clear due to its singly refractive property.