Nowadays, 90% of the world's rubies come from Burma. Prized for their purity and hue, the majority of rubies are sold to Thailand. The "Valley of Rubies", the mountainous Mogok area, 200 km north of Mandalay, is noted for its rare pigeon's blood rubies and blue sapphires. Human rights groups, however, have slammed the working conditions in the mines as horrendous.