All 3 +40 red cuts (bold brilliant delicate)
Fractured Amberjewel (tanks)
Solid Ocean Sapphire
Fierce/fine/inscribed ember topaz + some others (20 int+mastery one)
Etched/purified demonseye and a few others depending on market.
Think those are the main raid one's I cut to sell.
The greens, blues, and yellows you should get last. Sometimes you will do okay with them, most of the time their value is low so focus on the more profitable colors first.
Considering that the goal is to get all of them, I purchased the ones I would use for my own purposes, then after that I 'm just buying the tomes. Eventually I'll have them all and it will theoretically have taken less time than purchasing individual patterns.
maybe I'm misguided, but I think in the end I'll come out ahead
I am not profession expert but most used would be by my logic:
#1 agi,int,str gems. For dps and healers red socket, sometimes to others too if too small bonus.
#2 agi/resi, int/resi, str/resi for pvp yellow sockets.
#3 Spirit/int, for healers (prolly moonkins/SP/elemental) blue sockets.
#4 hit/agi, hit/str for dps blue sockets.
#5 hit/int for blue sockets, moonkins/SP/elemental might use spirit/int instead so they have 2 choices instead of #4 gem users who only have 1 choice.
#6 mastery gems. For tanks, idk about druids and not sure about dk but at least for pala and warr tanks yellow socket (desperate people put for non yellow sockets too for CTC)
#7 Mastery/stamina, mastery/parry for tank
#8 Orange gems that have str, agi, int and haste/crit/mastery
#9 dodge/agi gems for druid tanks
#10 Stamina gems for tanks who like it
#11 completionist
That is just my quick, not-experienced-with-professions, point of view.
Having a nice amount of alts to choose from I went for Brilliant first, then for Reckless, that gave me a way to get rid of 2 colours and make money, seeing as Int+crit seemed to sell higher than Int+Haste I went for that, that and also I needed it on my alts. Then I went for Purple and gathered Int+Spirit, useful for Alts and people never seem to not want healers. After that I'd recommend going for Mastery with other things, I'd ask around and check the AH, see what gems are selling and what gems aren't and if that doesn't make your mind up for you, I'd go with what gems are most useful for me. I have a lot of caster alts, so I went int, if you have a lot of melee go str, or your like hunters and rogues, go agil. I looked at it from a "How can I get use out of it and make money as well" standpoint, and it's making me money and saving me time too!