To identify raw gemstones, observe their hue, tone and saturation. The transparency, size and heft of a gemstone influences its identification, as does its luster and optical phenomena.
To begin with the identification, clean the stone with a gem cloth and use tweezers throughout the testing process to keep the stone clean from oils, fingerprints and any other dirt that may be on your hands. Next, determine the hue of the gem by using the Gemological Institute of America's gemstone identification chart. Look at the tone of the gem and identify how dark or light the color is. Assess the saturation for the intensity of the color. Warm-colored stones are typically constructed from reds, yellows and oranges and may have a brown tint. Cool-colored stones include those of reds, purples and blues and may have a grayness. Stones that have brown or gray tints are considered low-saturated stones.
The next steps in identification are to determine whether the stone is transparent, translucent or opaque and to determine the heft by bouncing the stone in the palm of your hand. Use a small light to check for optical phenomena. These small characteristics may be a small change in color, an additional sparkle or a floating shimmer. The luster is identified by using the small light and focusing on how the gem reflects the light.