Type IIa Diamonds
Type IIa Diamonds are the most valuable and consequently are very collectable items. They contain either very little or no Nitrogen atoms in the crystal structure of the stones. White stones are exceptionally colorless and fancy colored diamonds are often found with a brown, purple, or pink tone.
These diamonds have no measurable nitrogen or boron impurities. Among all diamonds, those that are type IIa are chemically the most pure. They represent only 1% - 2% of all diamonds.
Some Famous Type IIa Diamonds:
These are some iconic type IIa diamonds include the Koh-I-Noor, Elizabeth Taylor Diamond - “Krupp Diamond”, Darya-I-Noor, The Archduke Joseph, the Regent, the Agra, The Star of the South, The Beau Sancy, The Pink Legacy, The Artemis Pink, Rarest White Diamond and The Graff Venus.

Koh-I-Noor
Kohinoor / Koh-i-Nur, is one of the largest cut diamonds in the world, weighing 105.6 carats.

The Elizabeth Taylor Diamond
The Elizabeth Taylor Diamond, formerly known as The Krupp Diamond, is a 33.19 carat diamond.

Darya-I-Noor
The Daria-i-Noor is one of the largest cut diamonds in the world, weighing an estimated 182 carats. Its color, pale pink, is one of the rarest to be found in diamonds.

The Archduke Joseph
The Archduke Joseph is a colorless, antique cushion-shaped brilliant, weighing 78.54 carat.