What Exactly Is Moissanite?

Greetings Orchidians, I have followed this thread on Moissanite
for several weeks now, hoping that someone would clue me in on
the basics of the stone. I assume that it is manmade and
Moissanite is just the manufacturer’s trade name. I cannot find
it in the GIA handbook, or any of my guides to Rocks, Minerals
and Gemstones. What does anyone know about the following :
Chemical Composition

Crystal System
Refractive Index
Specific Gravity
Thermal Conductivity
Electrical Conductivity
Who makes or mines it? 
What is a typical price to the trade ($/ct.)?

Thanks for your help and a Happy Holiday Season to
all…Bob Williams