Blue sapphires are evaluated based upon the purity of their primary hue. Purple, violet and green are the most common secondary hues found in blue sapphires.Blue sapphires with any amount of green as a secondary hue are not considered to be of fine quality.Here's some facts/trivia about sapphires:*So strong is the power of a sapphire, it has been said that a venomous snake put in a vessel made of...