I havent used blackrock much so I can't confirm or deny anything for certain.
However from what I have read blackrock only has 2 known purposes
1.) If you carry blackrock in your pack it has a chance to "infect" creatures you come across. Infected creature are tougher and can have blackrock boxes on their corpses.
2.) Allow a GM+ mage or necromancer to try to cast the armageddon spell and end up with a permanent chance to blackrock infect creatures (Even if you arent carrying blackrock in your pack)
*EDIT*
I just remembered that when the blackrock event was first going on you could get aclaricity (sp?) scrolls that would allow short term fast skill gain when used. I don't think they spawn anymore but you might find one on a vendor. Probably wouldnt be cheap though.
I know I am probably in the minortiy here, but IMO you can actually start to PvP once you have trained skills to 90-100. Just use a good skill ring to boost your skills above that until they raise through play. Then switch over to jewelry that has other mods once your skills have increased.
