The value of diamond is estimated according to four qualities—carat, clarity,
color, and cut. However, only carat, a unit of weight, is an objective measure, since
a diamond’s weight in carats can be determined by an electronic scale. The
remaining characteristics have a partly subjective basis.
Clarity refers to the external cracks or to the internal flaws left in the
diamond when it is formed under intense heat and pressure.
The third quality is color, and in general, the less color, the better the
diamond. A tinge of gray or yellow can lower a diamond’s value. On the other hand,
a clear, bright yellow diamond, called a “fancy yellow,” commands a higher price
than the top-quality white diamonds.
Finally, the cut of a diamond is judged by the shape of the stone, its light
refraction, and how well it is polished.