How to Spot Garnets

Preparations

• 1

  Be sure your hands are clean so they do not mar the gem and distort the results. Have a light source available. The sun or a bright lamp will work just fine. If indoors, you want to be sure you have room to step back from the light.

• 2

  Hold the stone in front of and very close to your eye. Use a tweezers or other instrument so that your fingers do not cloud the gem. You want to be able to look through the gem without any distraction.

• 3

  Be sure your light source is far enough away from you. At least six feet is optimal. Adjust your distance so that you begin to see reflections as you look through the gemstone.

Apply the Simplifed Hodgkinson Method

• 4

  As you look through your gem, toward the light source, you should see a rainbow or rainbows of color appear. These are called refractions. Play with the gemstone's position and your distance from the light source until you can see these refractions quite clearly.

• 5

  Examine the refraction--the "rainbow" you see--for "birefringence." According to gemstone artist John Bailey on his website, birefringence is the "degree to which a doubly refractive gem separates the doubled images or rainbows." Note what you see.

• 6

  Now apply the simplified Hodgkinson Method. When looking at the stone, do you see double images, such as two rainbows on top of one another? Your stone is likely not a garnet. Do you see one rainbow with a green band, perhaps in the middle of the rainbow? Or a green band with a slight yellow band below it? This rules out the gemstone as a ruby. It may indicate a garnet.