The effect is our level 4 Damage Shield. Somewhat unfortunate it's not a higher level one, since it only does 2 damage, but it's good nonetheless. 3 second cast time, and no mana, so it's pretty good. Plus it stacks with all other classes DS spells. Somewhat disappointed in the stats, although the saves help out.
Do any of your people who post actually know what you are talking about? Yes the gems drop off wyverns in CS and none of teh gems they drop are junk. If you sold them to vendors you just cheated yourself out of 1-3K for each gem.
Some of the gems that drop off of wyverns in CS are not used for the Velious armor quests. For example flawed flame emerald, coral crescent, imperfect diamond, etc. They're just cash loots that you can sell to vendors for around 40p depending on faction/charisma.
FYI, Crushed Jaundice Gems and pretty much all other gems needed for these quest can be found on Sentient Armor in WL. Not exactly sure on their level, but its good exp up to 59. =P
The only gems that drop from the wyverns in Cobalt Scar are for the sleeve and leggings quests - NOT for the boot or other quests... they also drop a bunch of junk jewels to sell to a merchant for 45pp or so each..