I do not know if Dr. Moissan was trying to make diamonds, but he is
credited with the discovery of microscopic Silicon Carbide crystals,
along with diamond micro-crystals in a piece of iron-nickel
meteorite from Canyon Diablo. The only type of meteorite which has
yielded Moissanite is the iron-nickel type. The newer YAG is very
colorless (one variety) and makes, IMO, a far better diamond
simulant than CZ, at least in larger sizes, as far as durability
goes. As I posted earlier, I have cut a number of replicas of
customers' diamonds in colorless YAG and they were thrilled. I am
now working on a life-sized replica of the Taylor-Burton pear shaped
diamond for a customer who wants to present it to his wife as an
anniversary present, and it is being cut in colorless YAG.
YAG's dispersion is lower than both CZ and diamond, but in larger
stones, with very crisp facet meets and superb polishing (and a
private trick), the difference it is not very apparent.
YAG is also available in a super-intense pure yellow (Cesium-doped,
I think), a couple variations of rosy pink, a couple greens (one is
a perfect Tsavorite match, and, hey, it's got garnet structure to
boot....tricky to identify synthetic for the appraiser wanna-be's).
But my favorite is the YAG that changes from saturated bluish-purple
in incandescent to beautiful royal blue in daylight, just like the
finest (and properly oriented and cut) Tanzanite. The bonus, again,
is that it is MUCH tougher and harder than Tanzanite and brighter,
as well. I sell a LOT of this in larger custom cuts to jewelers who
like strong markups and have the clientele.
Yep, synthetic Moissanite crystallizes in the Hexagonal sytem (in a
couple different classes, though) and it's strong double refraction
drives me crazy to look at, although I will give credit to Charles &
Colvard for making sure it is usually cut with the C axis of the
crystal perpendicular to the table to minimize the effect if view
straight on to the table.