I’ve been thinking about your question about moldavite.
Origin: Whether you are buying cut or rough, this comes only from the Czech Republic. You will probably have to buy from a dealer, because the CR gov’t is very picky about anyone coming into the area to dig for the stones.
Color: Wide range. Look at good pictures of this stone. It ranges from a pale yellowy-green to almost black. Bubble inclusions are great; they contain the atmosphere on earth when the meteorite hit and exploded!
Size: Well, yeah. The bigger the better. But bigger is expensive.
Make sure you’re dealing with a reputable dealer, and ask about appraisals.