However, the star will only be visible If rutile's grow to sufficient density in 6 different directions.

During this, the structure becomes fixed.Īfter the formation or final processing of structure building in the sapphire, rutile needles grow following crystal structure while forming microscopic needles at 60 degree intervals. When a sapphire or rubies cool down from a semi liquid state, titanium dioxide present in it will crystalize after the sapphires cool down. Though being beautiful, the mysterious mechanism of internal reflection is quite simple. Chemically, star sapphire is an aluminum oxide and forms as trigonal crystals. A window into a sapphire crystal showing its trigonal crystal symmetry colorless silky center with nearly opaque blue outer growth.

In cabochon form, star makes the low grade Corundum also valuable. That is due to their asterism or internal reflection. Star phenomena in rubies and sapphires is common. It gives us two beautiful varieties of precious stones those are sapphire and rubies.

Ruby and sapphire stone