Burma (Myanmar) has a long history of producing some of the world's finest sapphires, renowned for their vivid blue color, high transparency, and exceptional clarity. The composition of these sapphires is the same as any other sapphire, which is a variety of the mineral corundum. However, what makes Burmese sapphires so special is their unique combination of color, clarity, and transparency.

The blue color of Burmese sapphires is due to the presence of trace amounts of iron and titanium in the corundum crystal lattice. The high transparency and exceptional clarity are the result of the geological conditions in which they formed. The sapphires are found in marble deposits that have been subjected to intense heat and pressure, which created an ideal environment for the formation of these gemstones.

Burmese sapphires are considered to be among the rarest and most valuable sapphires in the world.

The history of Burmese sapphires dates back to ancient times, with evidence of their use in jewelry dating back to the 7th century. The Mogok Valley in northern Myanmar has been a major source of sapphires since ancient times, and the gemstones were highly prized by the rulers of Burma and neighboring countries. During the British colonial era, the mining and trade of Burmese sapphires were controlled by European companies, who exported the gems to Europe and the United States.

Burma (now known as Myanmar) has a long history of producing some of the world's finest sapphires. Some of the most famous Burmese sapphires include:

1. The Blue Belle of Asia: This is a 400-carat cornflower blue sapphire that was discovered in the Mogok region of Burma in the early 1900s. It was sold at auction in 2014 for $17.3 million.

2. The Star of Bombay: This is a 182-carat star sapphire that was also mined in Burma. It was given to actress Mary Pickford by her husband, Douglas Fairbanks, and later donated to the Smithsonian Institution.

3. The Rockefeller Sapphire: This is a 62.02-carat cornflower blue sapphire that was once owned by John D. Rockefeller Jr. It was also mined in Burma and is now part of the American Museum of Natural History's permanent collection.

4. The Logan Sapphire: This is a 423-carat blue sapphire that was discovered in Sri Lanka but was cut and polished in Burma. It was donated to the Smithsonian Institution by Mrs. John A. Logan.

5. The Queen Marie of Romania Sapphire: This is a 478-carat sapphire that was mined in Burma and once owned by Queen Marie of Romania. It is currently part of the National Museum of Natural History's collection.

   Today, Burmese sapphires remain highly sought after by collectors and investors, with prices that can rival those of the finest diamonds. However, due to the political and social situation in the country, the mining and trade of these gems remain a contentious issue.