The document summarizes several precious stones and minerals, including their properties and locations found. It describes rubies as the second hardest gemstone found in Burma, Thailand, Madagascar and Tanzania. Emeralds are the only gemstone that is crystal clear green, found in Colombia. Blue sapphires are the most valued color of sapphires, located in Thailand, Madagascar, Tanzania and Australia. Diamonds are the hardest gemstone in the world, found colorless and valuable in India, Brazil and South Africa. Gold is a soft yellow mineral with great value, used in jewelry and is located in Australia, South Africa, USA, Canada, Indonesia, Peru, Russia and China.