Ruby is a precious gemstone known for its vivid red color, which ranges from deep crimson to bright scarlet and is caused by the presence of chromium. A variety of the mineral corundum, ruby ranks 9 on the Mohs hardness scale, making it one of the hardest and most durable gemstones suitable for all types of jewelry. Highly prized throughout history, rubies symbolize passion, power, and protection, and have been cherished by royalty and warriors alike. The finest rubies, often referred to as "pigeon's blood," are intensely saturated with a rich, velvety red tone. Major sources include Myanmar (Burma), Mozambique, Sri Lanka, and Thailand.