Firstly, let me ask you: Is this your first and only character? What are your professions?
Since these items can be used in blacksmithing, some tailoring, some leatherworking and the ocassional enchanting, it really depends are the rarity of the recipe they are used in.
For instance, Arcane Crystals sell (under Draenor) for on average 26g a piece. Why is this? Firstly and foremost, this is caused by the rarity of the gem. It's no found all that often in veins that are mined (I'm blacksmithing and mining and I've never found one : / ). Secondly, this is because arcane crystals are used to make Arcanite Bars in an arcanite transumte by alchemists. These arcanite bars are used in many, many blacksmithing recipes, paladin's epic mount quest, armor upgrades and a few other quests. These bars will sell for about 35g on average in the AH. Fun, fun, huh?!
Now, I'm going to give you what I think you should sell them in the AH for, but again, it depends on your server...if they are cheaper on your server, for instance, if Jade is going for 40s a piece on your server and I've told you to sell them for 50s, put it in for 35s and you'll be guaranteed to sell it. :P You basically just have to beat the lowest price.
Another suggestion would be to save ALL these gems for an alt. If you ever plan on making a blacksmithing (especially) alternative character, you will already have a lot of gems in your bank. This will come in handy. Even though you aren't making money off the character you're finding them with, down the line, you will SAVE a ton of money from the gold greedy AHers. That part is your choice, whether you want to save them. I will tell you that when I started blacksmithing and I started my paladin, I saved EVERY gem I ever touched...never AHed it and never vendored it. My bank is filled with sapphires, diamonds, malachite (still), moss agate, moonstone, jade and suchforth. I have never had to buy any gems for farm for them. The only time I have bought gems is for my Heartseeker Plans (they are ridiculous to make) and for any low level weapons for guildies that I didn't have gems for.
Okay, so prices...here I come!
Tigerseye: 1-2s
Malachite: 2-3s
Lesser Moonstone: 30-40s
Moss Agate: 15-30s
Shadowgem: 20-40s
Citrine: 30-50s
Aquamarine: 30-40s
Jade: 40-50s
Star Ruby: 80s-1g
Azerothian Diamond: 3-5g
Blue Sapphire: 5-7g
Small Luscious Pearl: 30-50s
Iridescent Pearl: 50-80s
Pristine Black Diamond: 1g (these are really only used in the paladin epic mount quest and aren't even able to be sold to a vendor - they could be used in other quests, but the mount is the only one I can think of and they only need one)
Black Pearl: 8-10g (not sure, never sold one :O)
Golden Pearl: 10-12g (used to make Mooncloth Robes by tailorers)
Blue Pearl: 3-5g (also used in a quest from the Badlands)
Large Opal: 3-5g
Arcane Crystal: 26-28g
Some of these prices are more than double what a vendor will buy them back for, but that's what I've seen them in the AH.
If I'm a little off on some (such as the black pearl, blue pearl and sapphire, please feel free to edit)
Hope this helps.
Ay