1. Often imitated, never duplicated
Diamonds are not the only gems that impersonated by less-expensive stones. Other naturally-occurring blue-hued rocks include blue spinels, blue tourmalines, tanzanite, iolite, and in some circumstances, colored glass, and rogues sometimes switch these stones for the real thing.
2. Sapphires have a sister stone
Surprisingly, red rubies are almost identical to blue sapphires in their chemical composition. Because they both have asymmetric crystal structures, unlike other stones, their hue and saturation are dependent upon their being polished in the correct direction. This is called birefringence.
3. Almost as hard as diamonds
Of the naturally-occurring minerals, diamonds are known to be the strongest and are given a 10 out of 10 on the Mohs scale. Sapphires, amazingly, are not far behind, with a 9 out of 10.
4. Used for practical purposes, too
It’s not only for their natural beauty that the stones are prized. In addition to their ornamental uses, sapphires are utilized in manufacturing processes, to make wristwatch crystals, durable windows, electronic wafers, and other high-tech instruments.
5. Some sapphires are rock stars
A rare needle-like inclusion within its crystal lattice can make sapphires appear to have a six-pointed star on its face, when it is illuminated from above by only a single light source. If two of these inclusions are present in the same stone, a 12-pointed star appears up top.
