The July birthstone is the Ruby. Ruby is the most valuable variety of the corundum mineral species, which includes sapphire. In fact, Rubies can command the highest per-carat price of any colored stone. In its purest form, the mineral corundum is colorless. Trace elements that become part of the mineral’s crystal structure cause variations in its color. Chromium is the trace element that causes ruby’s red color. Rubies can range from an orangy red to a purplish red depending on how much chromium is present during formation (the more chromium, the stronger the red color).
The most renowned rubies–like those from Myanmar, the Himalayas, and northern Vietnam–typically form in marble. They’re found in layers that are distributed irregularly within the surrounding marble. Marble forms, as part of the metamorphic (rock-altering) process, when heat and pressure from mountain formation act on existing limestone deposits.
Red is the color of our most intense emotions—love and anger, passion and fury. Early cultures treasured rubies for their similarity to the redness of the blood that flowed through their veins, and believed that rubies held the power of life.
Ruby is one of the most historically significant colored stones. Rubies are mentioned four times in the Bible, in association with attributes like beauty and wisdom. In the ancient language of Sanskrit, ruby is called ratnaraj, or “king of precious stones.”
Ruby has accumulated a host of legends over the centuries. People in India believed that rubies enabled their owners to live in peace with their enemies. In Burma (a ruby source since at least 600 AD—now called Myanmar), warriors possessed rubies to make them invincible in battle. However, it wasn’t enough to just wear the rubies. They had to insert them into their flesh and make them part of their bodies.
The name ruby comes from the Latin word ruber, which means “red.” The glowing red of ruby suggested an inextinguishable flame burning in the stone, even shining through clothing and able to boil water.