* If Gemstone Is Single Refractive, The Stone Will Be Dark,If Double Refractive, You Can See The Brightness Around The Gem stone When You Are Rotating The Gem stone.

HOW TO USE THE DOUBLE CARD

Step 1 : Keep The Card Near Sunlight Or Torch Light

Step 2 : Keep The Gemstone Middle Of The Card (Between Both Polaris Card)

Step 3 : Rotate The Gem Stone To Check Single Refractive Or Double Refractive