CS Book 2 _AS-8 Color.pdf

Colored Stones 8 KEY CONCEPTS You should judge a gemstone’s beauty and value only by When you can’t control the lighting conditions in a buying comparing it with others of its own species or variety. situation, use your own comparison stones or color samples. Large stones with...

Colored Stones 8 KEY CONCEPTS You should judge a gemstone’s beauty and value only by When you can’t control the lighting conditions in a buying comparing it with others of its own species or variety. situation, use your own comparison stones or color samples. Large stones with fine color are more common in some Consistent procedures are very important when grading colored stone species than in others. colored stones. Know a gem’s identity before you grade it. In many gemstone varieties, pure hues are more valued than mixed hues. In general, attractive colored stones tend to have highly saturated hues and medium to medium-dark tone. You shouldn’t use trade terms that imply a gem’s geographic origin if you can’t be sure of its actual source. Hues with very light or very dark tone usually don’t reach the same high levels of saturation as those with medium tone. The way a gem is cut can have a dramatic effect on its face-up color. Larger stones can appear more saturated than smaller stones cut from the same rough. The cutter’s main goal is to produce a stone with the highest Some stones reach fine color only in large sizes, others only in possible value. small sizes. If rough is very valuable, cutters often compromise on Most defects in colored stone proportions are compromises proportions to save weight and avoid loss of money. made by the cutter to produce economically viable gems. Cutting compromises that save weight can also cause Many gemstone species share some of the same hue and extinction, windows, or both. saturation ranges. 106