Moissanite has a property known as double refraction. When a ray of light passes through the gemstone it is slowed, bent and split in two.
Sapphire is a doubly refractive material as well, as are peridot, tourmaline and zircon. To some degree it is this property that gives Moissanite its amazing fire. However it is
often cited by critics of Moissanite, typically by companies who sell CZ, as a disadvantage, claiming that the double refraction will make the stone appear blurry. What
they don't say is that every double refractive gem has at least one direction in which the material behaves like a singly refractive gem. This is referred
to as the optic axis, and does not break light into two rays.
Moissanite is cut so that this direction of single refraction is though the table. This means that the
doubling is not apparent when the stone is viewed though the table (top of the stone). Moissanite must be viewed at 10x magnification (jewelers loupe) through any other
crown facet (e.g. star, or bezel) to see the doubling. Most of our customers do not know or realize that Moissanite is double refractive, and we provide this explanation
and images to explain that, although it is a unique property of Moissanite, it does not negatively effect its beauty.
Below is a picture of an emerald cut Charles & Colvard created Moissanite. It is a rare stone as the emerald cut is not normally offered.
However we feel it is very illustrative when explaining Moissanite's double refractive properties. If the doubling were easily seen in a
brilliant cut stone (and it is not, as explained above), it would be even more readily apparent in a step cut such as an emerald cut given
its long straight lines. However, based on the picture below you can see that it is not.