Rubies are bright red gemstones from tough corundum that sparkle like cherry juice in light, making strong, lasting jewelry people have loved for thousands of years.
Rubies are red versions of a tough mineral called corundum, which is made from aluminum and oxygen. That's why people sometimes call them 'red sapphires,' since sapphires are the other colorful kinds from the same family.
Rubies form deep underground where heat and pressure squeeze rocks together over millions of years.
The most famous spots for rubies are in Myanmar, like the Mogok Valley, often called the 'Valley of Rubies.' That's where the best, brightest reds come from.
The most prized rubies glow with a pure, deep red called 'pigeon's blood' red, bright and lively without too much orange or purple. Clarity, size in carats, and a perfect cut that makes light dance inside also matter.
The Sunrise Ruby is a 25-carat beauty from Myanmar that sold for $30 million at an auction in 2015. That's a record for colored gems.
Kings and warriors used rubies to decorate armor and horse gear, hoping they would bring luck in battle. In places like India and China, people placed rubies under house foundations to invite good fortune and protect families.