This is one of the most popular among consumers and gemologists alike. Mainly due to the fascinating display of a floating star across the top of the gemstone that changes with the lighting environment in which it is viewed.

 

What causes a star?

Stars are caused by light traveling perpendicular to the crystal faces along tiny fiber-like inclusions. Which is why it is very, very rare to find a transparent star stone. If you look at the corundum crystal to the left you will see the path that light travels in the stone to go perpendicular to the crystal faces. Now look at the star ruby above and see that the ruby has a six rayed star just like the black lines shown on the crystal. This is how a six rayed star is formed. And if you look at the photo below you will a star diopside which has a four rayed star due to it having four crystal faces for the light to travel through. And in the photo at the top of the page you see a black star with a six rayed star like the star ruby. This is a black star sapphire. Although they are black like the diopside the black star sapphires are more expensive than the diopside stars. So be careful when you shop for a star stone to count the number of rays the star has. It will help you know that you are getting the correct stone.

Star Diopside showing four rayed star ....and a very rare 6 rayed Star Opal.