The color comparison card tray can be used to identify the colors of diamonds and gemstones. Easy to use. The colorimetric card can observe the color of the itself of a colorimetric lamp. When grading diamonds, a dedicated colorimetric light is used, and a colorimetric board or paper is used as the background. The whiter the color, the rarer and more the . The size is approximately 12.5x9cm/4.92x3.54inch. Foldable. Easy to carry. Package includes: 1x Grading Card