Star Rubies are a rare variety of the gemstone Ruby. These magnificent gems display a sharp six-rayed star which seems to glide magically across the surface of the gem when the latter is moved. This is caused due to an optical phenomenon known as "Asterism". The star is best visible when the star ruby is seen in a single light source such as sunlight and spotlight. Star-effect or "asterism" is caused by the dense inclusions of tiny fibers of rutile (also known as "silk"). The stars are caused by the light reflecting from needle-like inclusions of rutile aligned perpendicular to the rays of the star. However, since rutile is always present in star rubies, they are never completely transparent. In fact, star ruby is one of those few gemstones which actually require inclusions (i.e. rutile).
!
SwissGemShop
Your source of loose Precious & Semi Precious Gemstones Gem quality Gemstones at sale price A lot of information to learn about Gemstones