Why have prices for these been going up for the last week or so, while the prices on all the other flawless squares have been going down? Was there some change with crafting that I missed that is inflating the value of these gems in particular?
Only thing I can think of is that they are the most sought after gem since 2 classes use dex, and I think pretty much everyone like crit damage increase.
No crafting changes, it must simply be that there are more people buying them than there are selling them at the minute. I think green is the highest in demand, demon hunters seem to still be the most played class, and the majority of people use green in weapons also. It takes a lot of flawless squares to get all the way up to 100+% crit damage in a weapon.
It may also be that with the commodity RMAH going live that more people are using flawless to turn into radiant star (which is the first gem that seems to sell for the minimum rmah value of $1) and people are moving cash quicker than gold selling by selling higher level gems - especially if they have recipes for the gems beyond that. So people may be buying up flawless in general for that purpose; and again, green is the one that sells the quickest/for the most, so people may have invested in the green JC patterns first.