Diamond The diamond is the most popular of all gemstones. The diamond is the highest valued precious stone, which takes millions of years to form. A diamond is a mineral compound made of pure carbon and is the hardest natural substance on the planet. Diamonds are so strong, they can only be cut or polished by another diamond. The name itself is derived from the Greek word “adamus,” which means “invincible.” Diamonds are typically colorless, but yellow, brown, green, gray, black, pink, blue, red, and purple stones can also be found along the diamond color spectrum. Jewelry-grade diamonds are rated based on color from bluish-white to yellow, and on clarity, which ranges from pure to various levels of flawed. Diamonds are measured in carats—the higher the carat weight and purity level of a stone, the more valuable the gem. The diamond is the birthstone for April. Emerald Known for its brilliant green color, emerald can also have blue or yellow undertones and loses all color when subjected to high heat. Their brittle exterior makes emeralds difficult to shape.The earliest emeralds were mined in Upper Egypt as early as 2,000 B.C. They were mined throughout the reign of Alexander the Great and were well-loved and collected by Cleopatra. The Aztecs and Incas also coveted emeralds, and the Moguls of India revered them so much they inscribed the gems with sacred text to be used to ward off evil. Historically, emeralds have been mined from Russia, Austria, Australia, and Norway. Today, the majority of emeralds are found in Brazil, Zambia, and Colombia. The emerald is the birthstone for May. Ruby The ruby is a pink to deep red precious gemstone. The name comes from the Latin word for red, ruber. Rubies are said to attract good luck for the wearer. Ancient Hindus believed rubies were a sign of protection from evil. Today, the ruby has come to symbolize love and passion. Rubies were also highly prized by ancient Chinese warriors who were known to wear rubies on their armor. Most rubies today are mined in Africa and Southeast Asia. The largest mined ruby weighing in at four pounds, the Liberty Bell Ruby, was stolen in a heist in 2011. The ruby is the birthstone for July. Sapphire Sapphires come in a variety of colors, but are mostly associated with blue hues. A sapphire of another color, like pink, white or yellow, is generally called a fancy sapphire. The blue sapphire represents peace and serenity. It is seen many times in ancient religious writing to symbolize purity, wisdom, loyalty and faith. Sapphires are mined throughout Africa and Asia, but can be found in Australia and the U.S. The sapphire is the birthstone for September.