Blue sapphire is one of the most popular gemstones in the world and has been for centuries. Sapphire is the ruler against which all other blue gemstones are measured. Blue sapphire is said to represent faithfulness, nobility, truth and sincerity. Sapphire is a member of a family class of stones known as corundum. Corundum is made up of two of the three most abundant elements in the earth’s crust: aluminum and oxygen. For corundum to form there needs to be an environment rich in aluminum and oxygen that is also free of silicon, the second most abundant element in the earth’s crust. Blue sapphire, like pink sapphire, ruby and all corundum is rated as a 9 on the Moh’s hardness scale. This means blue sapphire is an excellent choice for use in sapphire rings, sapphire earrings, sapphire necklaces and all sapphire jewelry. Sapphire holds up to normal wear and tear better than emerald, garnet, aquamarine and the vast majority of other precious stones with the exception of a diamond.