What you should know about a diamonds color
When jewelers speak of a diamond's color they are usually referring to the
presence or absence of color in white diamonds. Color is a result of the
composition of the diamond, and it never changes over time.
Because a colorless diamond, like a clear window, allows more light to pass
through it than a colored diamond, colorless diamonds emit more sparkle and
fire. The formation process of a diamond ensures that only a few, rare diamonds
are truly colorless. Thus the whiter a diamond's color, the greater its
value.
(Note that fancy color diamonds do not follow this rule. These diamonds,
which are very rare and very expensive, can be any color from blue to green to
bright yellow. They are actually more valuable for their color.)

America has gone the furthest towards a universal color grading system. The
standard devised by the well-known Gemological Institute of America, or
otherwise known as "GIA," has become the most widespread standard used for
grading diamonds for color. The steps of the system represent from colorless to
yellow: D E F G H I J K L M N O P Q R S T U V W X Y Z. The top grade is coded as
D, or completely white. At Sawyer Jewelers we feel the need to carry no less
than a J in color and recommend no less than I in color if you are setting the
diamond in a whit gold mounting.
Diamonds from colorless, or D color, to those that are yellow or yellowish
brown are grouped into the diamond color scale
Fancy Color
It is often surprising to learn that diamonds also occur by rare accidents of
nature
in shades of pink, blue, green, amber, or even red. These rarely occurring
colors are referred to as fancies and are evaluated by a different set of color
standards. These standards take into consideration various factors such as hue
and saturation. Fancy colored diamonds are the most expensive because of their
extreme rarity. Some fancy colors can cost hundreds of thousands of dollars for
diamonds of one carat or less!
The physical conditions necessary to color a diamond naturally occur very
seldom, making natural color diamonds extremely rare. For every natural color
diamond, there are 10,000 colorless ones that have made the trip from the
earth’s depths to its surface. It is this entirely natural process of
geographical formation which ensures that each natural color diamond is one of a
kind.
The formation of natural color diamonds is a process that requires the
presence of additional trace elements and distortions to the typical diamond
crystal. During the creation of a diamond, if an element interacts with its
carbon atoms, the color can change. Natural radiation and pressure on a
diamond’s structure can also intensify its color
Fluorescence
Fluorescence is not directly related to a diamond’s color. This separate
characteristic refers to the diamond’s ability to fluoresce under ultraviolet
(UV) light. Our sun emits some UV light, but it is usually not great enough to
detect fluorescence. The most common source of UV is a black light (like at a
dance club) when exposed to UV light, many diamonds will give off a distinctive
glowing blue coloration. Although fluorescence may be displayed in various
colors, blue is the most common in diamonds. The fluorescence of a diamond is
defined by its intensity as either None, Faint, Medium, Strong, or Very Strong.
Although fluorescence is a characteristic that can be measured, it is seldom an
issue when selecting a diamond.