White sapphires and diamonds are extremely hard gems often used by jewelry makers for expensive rings, earrings, necklaces and other pieces. While both are hard and brilliant, they are composed of different elements and have different properties. White sapphires belong to the corundum gem family, which also includes rubies, colored sapphires and padparadschas. Diamonds are pure carbon, the same element making up graphite and charcoal. Some gem purchasers shy away from diamonds because of the “blood diamond” controversy, in which diamonds are used to finance wars, especially in Africa.

White Sapphires Are Pure

Aluminum oxide is the main ingredient in corundums. Impurities, including, iron, chromium, copper, titanium and magnesium, give corundums their characteristic colors. White sapphires lack impurities, leaving them clear and colorless. Compared to diamonds, white sapphires are softer and have a lower refraction index — they sparkle less than diamonds do. Sapphires scratch more easily than diamonds, but diamonds are more prone to chipping because of their crystal structure.

Diamonds Are Hardest

Diamonds are the hardest and most thermally conductive naturally occurring substance. Their hardness stems from the lattice structure of their carbon atoms. Diamonds form in the Earth’s mantle under conditions of high heat and pressure. They reach the surface through volcanic eruption, whereas sapphires form on the surface, in sedimentary rock deposits such as riverbeds. Diamond rings, because of their superior brilliance and contrast, need cleaning –using a soft toothbrush and a special paste — less frequently than do white sapphire rings to maintain their sparkle. That sparkle also makes diamonds a popular choice for wedding rings, although many people have trouble telling the two apart unless the gems are viewed side by side.