Star Gems
Star gems are not a specific variety of gemstone but rather a fascinating variation of other stones. The best known examples of star gems are rubies and sapphire.It's important not to confuse star stones with diamonds and diamondlike gems. Ordinary diamonds are often shown as radiating a star - this is not the same as a star stone. In addition moissanite is a diamond simulant crystal often marketed as being "the star gem" because of its origin.
What Are Star Gems?
Star Gems are examples of various stones that appear to display an internal star when viewed under the right lighting conditions. This starring property is known technically as asterism.The star effect is caused by the presence of small amounts of impurities (rutiles) in the stone. Different gemstones will reveal different forms of star depending on their chemistry and the exact nature of the rutile inclusions. Six pointed stars are most common, however four pointers are sometimes found.
It's usually difficult if not impossible to see the star effect clearly under diffuse indoor lighting. Instead the asterism shows up best under direct light. Most stars can be seen under light from the front, however some stones such as rose quartz need to be lit from behind.
Uses
Star gems are usually shaped and polished into smooth cabochons rather than cut into a faceted gem. You can buy them set into almost any jewelry but they're most effective in pieces such as pendants that display their star effect at its best. The metal setting will be influenced by the nature and colour of the stone, gold, silver and platinum all commonly used.Natural star gems are rare and valuable, the best examples with the clearest stars can fetch a high price. For those of us without deep pockets, star gems can be created in the laboratory and are much more affordable. These synthetic stones also tend to have a more perfect star which is brighter and visible in a wider range of lighting conditions than the natural stones.
If you buy affordable star gem jewelry today the chances are that the stone will be created rather than natural.