The Hard Facts of Sapphires and Rubies

Ask any jeweler to list the gemstones with which they prefer to work, and sapphires and rubies would undoubtedly rank near the top. With a hardness of 9 on the Mohs scale, these popular varieties of corundum have long been considered nearly impossible to damage, and they can easily withstand the melting point of even high karat gold solders. Not surprisingly, many jewelers feel a comforting sense of security when faced with a ruby- or sapphire-set piece. Which may be a problem.