Many cultures around the world valued, and still value, emeralds as a particularly valuable precious or gemstone. Brazilian emeralds are famed for their intense green colour, in some cases even fetching more money than a comparably sized diamond. The preferred cut for clear emeralds is the so-called ‘emerald cut’ octagonal step cut, named in their honour and developed in response to the stone’s sensitivity to shocks. The first emerald mines were located in ancient Egypt and began production in the 13th century BC. For over one thousand years the mines of Sikait and Zabara supplied Europe with this precious mineral. Emeralds were also highly prized in the Orient, for example by Persian, Ottoman and Mughal rulers. When the Spanish conquered South America in the 16th century they discovered a booming trade in the stones which was based in Columbia and extended as far as Chile and Mexico. From that time onwards the mines in Muzo, seized by the Spanish in 1573, replaced Egyptian sources. Today 55 percent of the world’s emeralds come from Columbia.