What to do with uncommon gems

So, now most people has already leveled JC, at least to the point of not needing Uncommon Gems anymore (after all, you need those only until 475... once you get there, if you're not in a hurry, you could use them just for the dailies). The prices for those gems are more or less lowering, but if you, as I do, prospect some Elementium Ore ore Pyrite Ore every day and there are still good profits to be made from everything you get from them... You just need to know how to sell the Uncommon Gems.
So, let's see gem by gem what can be done:

[Carnelian]: The disenchantable item made by Carnelians, [Carnelian Spikes], is rarely used while leveling, because with 460 skill points in JC you also learn [Nightstone Choker], which requires two gems instead of three and can proc a blue item ([Nightstone Choker], which can be disenchanted for a [Heavenly Shard] or even sold, since it has ilvl 325). If Carnelians, raw or cut, don't sell well in your server, you should probably check if the price of a [Inferno Ruby] is more than 3*[Carnelian]+3*[Heartblossom]. If that's the case, use [Transmute: Inferno Ruby] or look for an alchemy to do that for you. Please note that this Transmute doesn't have any CD.
Update: As said by Vince in his blog, you can do a good profit also from disenghanting [Carnelian Spikes], since these provide two [Greater Celestial Essence] on average. This wasn't so profitable on my server when I first wrote this post (Inferno Ruby were selling for crazy prices), but you should really consider this.

[Hessonite]: Most of the times, Hessonites still sell well. This is because of people trying to level JC creating [Hessonite Band] which can be disenchanted and that sometimes procs a blue item ([Hessonite Band]), in a similar manner of what's happening with the Nightstone. The problem is, there isn't a daily that requires Hessonite, so you have to accept the price at which it normally goes on your AH... I don't really have any advice for this one, but it should still sell well. If it's price is really low, consider making the Hessonite Band yourself to disenchant it, or to transmute the gem... I don't think you'll need to do either of the two for sometime, but it's very server-dependant

[Nightstone]: Nightstone can be used from Jewelcrafter to make [Nightstone Choker], which can be disenchanted and greys out at 515, so lots of JC/Enchanter will keep doing it because they can get back the price of the mats. If you see that despite this its price is too low wait for the daily requiring them, A Present for Lila.

[Zephyrite]: This can be quite hard to sell, except for the days in which it's needed for the JC daily. On my server (and I've read it's the same also for others), this can go from 30g when there isn't the quest to 100g the day of the quest, so you should keep them for that day. In the last days I'm always checking early in the morning if the daily involves [Zephyrite] and if that's the case I buy every [Zephyrite] at less than 100g and relist-them, one-by-one or in groups of three: and everything sells before evening.

[Jasper]: Since Jasper is used to level JC from 425 to 450 (it greys out at 485) and most JCs started the expansion having already 450 in their profession, there isn't really a demand for it... This makes him very difficult to sell raw, but also a really good way to make enchanting mats. To make a [Jasper Ring] (that can proc [Jasper Ring]... But depending on your server economy, this proc could be less caluable than the green item, since it disenchants in [Small Heavenly Shard]) you just need one Jasper, and most of the times you'll get 2 [Hypnotic Dust] or 2 [Lesser Celestial Essence]. You should notice that there is a JC daily requiring Jasper, so the strategy  used for Zephyrite should work also with Jasper. If enchanting mats don't sell well on your server you should keep your Jasper and sell it the day of the daily.

[Alicite]: Alicite is the most difficult gem to sell. Transmuting it won't work: the raw [Amberjewel] doesn't seem to sell well (check your AH just to be sure), and the [Alicite Pendant] (blue version: [Alicite Pendant]) requires two [Alicite] to make, so the value of the enchanting mats won't be a lot higher than that of the alicites you used to make them. Right now I'm dumping mine in the AH, avoiding doing so in too much high numbers (I don't want the prices to collapse even more) and I think you should do the same... Prices of all these green gems will keep going down for a while, so you don't want too much of this in you bank when they'll be selling for 10 golds each.

Now, to help you visualize what you can make with transmutes (the easy escape when the difference between uncommon and rare gems widens) and to see if I still know a bit of html, here is a table with the mats and what you get for each transmute:

3[Carnelian] + 3[Heartblossom]	=	[Inferno Ruby]
3 [Hessonite] + 3 [Cinderbloom].	=	[Ember Topaz]
3 [Nightstone] + 3 [Twilight Jasmine]	=	[Demonseye]
3 [Zephyrite] + 3 [Azshara's Veil]	=	[Ocean Sapphire]
3[Jasper] + 3 [Stormvine]	=	[Dream Emerald].
3[Alicite] + 3 [Whiptail]	=	[Amberjewel]