Lab Grown Blue SapphirePureGem lab grown blue sapphires are physically and optically identical to mined sapphires the same corundum crystal structure, the same 9 Mohs hardness, and the same rich, velvety blue that has made fine sapphire one of the most coveted coloured stones in the world. The finest blue sapphires are described by gemologists as a vivid, deep royal blue and every PureGem sapphire is individually selected to meet or exceed that standard. Conflict free,