Cut
A diamond’s brilliance is largely
determined by its cut. An expertly-cut diamond with perfectly symmetrical and
aligned facets will reflect light beautifully, leading to unrivalled
brilliance. True expertise is required to create facets with perfect
proportions that maximise light and increase a diamond’s signature sparkle.
Clarity
Diamonds are created by tremendous
heat and pressure deep within the earth. This thoroughly organic process means
that virtually all diamonds contain internal inclusions and surface blemishes.
Diamonds with fewer of these characteristics are deemed to have a higher
clarity, ranging from FL, or Flawless, to I, signalling a number of inclusions.
Colour
White or colourless diamonds exist on a scale of many
different shades, ranging from brilliant white to pale yellow. These subtle
differences are graded on a colour scale from D (colourless) to Z (light
yellow). Beautiful coloured diamonds, in hues of yellow, pink, blue, orange,
green and red, for example, go beyond all other measures of rarity, and a
graded based on their intensity and enticing depth of colour.
Carat
In the ancient world, carob seeds
were used as a reference for the weight of individual diamonds. Today, this
historic practice has led to the word carat, which is now the contemporary
measure of weight for all diamonds. Precise measurements are taken to the
hundredth decimal place to ensure complete accuracy. A metric ‘carat’ is
defined as 200 milligrams.
All of this information is quoted exactly from here.
To start from the beginning, click on Lucy’s image.

This mini series on Diamonds has
four parts to it. Click on each link separately to learn more about diamonds.
How
the diamond engagement ring came to be
How
De Beers became the diamond industry leader
The
"Diamonds are Forever" slogan
The
4Cs Of Diamonds