The apex
Diamonds are forever is a very well known slogan. Some diamonds have been around for billions of years and will be around for another few billion years to come. Not only have they been around for ages they also possess luster, fire, it's the toughst material and there is a very big variety of colors and hues. With other words it possess a combination of features no other gemstone has.
This is what makes diamond the apex among gemstones.
Most Desirable
Diamonds that are ranked D on the diamond color chart and have no inclusions, no visible fluorescence and have a perfect cut are considered top quality.
These are the most sought after or most desirable colorless diamonds.
For fancy color diamonds there is one major difference. Those diamonds are all about color. The color chart for fancy diamonds ranks from fancy light to fancy vivid.
The most desirable among them baring a fancy intense or fancy vivid color.
Value
Diamonds are graded by carat, color, clarity and cut also known as the 4Cs. These four factors describe every aspect of a diamond and they are together the main system that determines a diamonds value. One more factor remains and that is fluorescence. The 4Cs determine the value of a diamond with the lack or presence of color beeing the most important factor.
For colorless diamonds there is a diamond color chart ranking from D to Z. On this chart D is the most valuable and Z is the least valuable. Beyond Z there is an increase in value because the diamond is no longer classified on the colorless diamond color chart and now belongs to the fancy color diamonds.
Fancy color diamonds are found in a wide variety of colors black, blue, brown, green, orange, pink, purple, red and yellow. Red diamonds are the rarest diamonds in the world only a handfull are known to exist. Pink and blue are among the most sought after fancy color diamonds and brown and yellow are the most common though they are still a rarity.