The most famous and brilliant natural diamonds in the world are 11A!
The Koh-I-Noor, The Elizabeth Taylor Diamond (Krupp), The Regent Diamond, The Star of The South are all famous type 11A diamonds. Only the best 1 to 2% of mined diamonds can be called Type 11A. They are the purest and thermally conductive of all diamonds. As natural diamonds rise toward the surface of the earth from the depths, they are usually deformed of form imperfectly taking on certain impurities. Type 11A stones are almost entirely devoid of these imperfections and deformations. All ALTR created diamonds are Type 11A.