Cullinan Diamond
The Cullinan Diamond is the largest gem-quality rough diamond ever found, weighing , discovered at the Premier No. 2 mine in Cullinan, South Africa, on 26 January 1905. It was named after Thomas Cullinan, the mine's chairman.
Royal Asscher Diamond Company
In 1903, at , the Excelsior diamond was the largest diamond ever found. The gem required expert handling to be properly carved: inclusions within the rough diamond prevented it from being polished as a single stone. Abraham Asscher was charged with cleaving the Excelsior; to minimize flaws, he carved the stone into ten diamonds which were primarily sold to anonymous purchasers. Rumor and myth abound regarding the location of the diamonds.