Legends tell us that the three intersecting rays are thought to represent faith, hope and destiny. Ancient cultures have thought that star sapphires had demons or angels of light living in them,and because they turned dark at night, they were thought to go to sleep. The best stars will have just enough silk to create the star effect, but not so much as to harm the transparency and color.
Natural stars are normally non-heated stones.
The rutile silk is what actually forms the star. If a stone is heat-treated then you lose its star because the rutile needles are destroyed when heated. If a fine star ruby or sapphire is properly lit, the needles reflect the light in such a manner that it appears the star is hovering over the gemstone. The star wanders as the light is moved. One will have good color and a bad star.