I think we've been needing one for a while.
Forum Veterans please feel free to correct me/add information in replies. Thanks!
1. What is blackrock?
Blackrock is a substance that first appeared in Britannia during the war with the Ophidians (2006). A strange pillar appeared in the bottom of Terathan Keep, which when destroyed showered pieces of blackrock in the dungeon.
2. What is blackrock good for?
Blackrock is the reagent for the Armageddon spell. Armageddon, when properly cast, would result in the annihilation of all life on Sosaria. So far, no one has been able to properly cast it. Any Mage or Necromancer of at least GM skill can attempt to cast Armageddon. To do so, you must possess a piece of blackrock, which you place on the ground near you. Then you say the following words of power: vas kal an mani in corp hur tym. If you're unsuccessful, you'll get a message that "you feel uneasy." If you're successful, one of several things can happen:
__a. You'll wave your arms a little as if casting a normal spell (if your hands are free and you are not mounted on a pet).
__b. The blackrock will explode, blowing you several tiles away, and damaging you.
__c. The blackrock will explode and kill you. Your body parts will be scattered around the area, and your possessions will be in a backpack near the torso of your body.
__d. A Wisp will appear and attempt to communicate you. It will even follow you around for a short while, before departing.
3. Where do I find blackrock?
Currently the only way to acquire blackrock is to dig up a piece while mining. To dig up blackrock you must be a GM miner, either naturally or with use of Blacksmith Gloves of Mining, which means you can dig blackrock with 95 mining if you have the Ringmail Blacksmith Gloves of Mining. Blackrock can be found in any normal mining spot, will drop into your backpack along with a message that you have found a piece of blackrock. This message is similar to the message you receive when you dig up a Mondaine's Legacy gem. Be aware that blackrock is a rare drop, and you will not find a lot of it. You can improve you chances by mining in Felucca, with all the usual cautions in effect. Mined blackrock is very small and hard to see in the 2d UO backpack, so you may not realize you have a piece.
4. I dug up a Blackrock Elemental! Help!
Blackrock Elementals are bad news. The developers designed them to deter script mining, and also to provide a penalty for daring to dig for blackrock. Blackrock Elementals look like Shadow Iron Ore Elementals, but are titled A Blackrock Elemental in red script. The Blackrock Elemental is very close to unkillable, is as fast as a Paragon, has a huge number of hit points and powerful hit point regeneration. They suffer no damage from pets, spells or summons creatures, and reflect all damage at the rate of 50%. If you are near a town they can be lured there and guard whacked (I speak from experience here). Otherwise it is best to lure them away from your corpse so that you can gather your belongings.
5. I cast Armageddon, and now I hear voices!
You are infected by blackrock. As of this writing, what this means to the infected character hasn't been revealed by the developers, but it results in a couple of phenomena:
__a. You begin to "hear voices" (text messages in your play window). These range from greetings (Good Morning!) to incitement to murder (Kill them! Kill them all! Tear them to pieces!).
__b. You begin infecting creatures, NPCs and monsters nearby with Blackrock sickness. This results in the creature turning red, becoming more powerful, and attacking players on sight. Any creature that has a chance of dropping a treasure map will, when infected by blackrock, have a chance to drop a special treasure chest.
6. I just infected a cat and I didn't even cast Armageddon! What gives!
It is possible to infect creatures with Blackrock sickness simply by carrying a piece of blackrock in your backpack. If you don't wish to infect creatures, put the blackrock in storage.
7. Who are these "Traders" I've heard of that give rewards for blackrock?
Mysterious people in black shrouds titled "A Trader" appeared in the town of Haven recently, offering incredible rewards for blackrock. These ranged from Mondaine's Legacy Peerless ingredients and gems, to Doom Artifacts and Tokuno Treasure artifacts, to upper level Runic Hammers and Ancient Smithy Hammers. The Traders have since disappeared, and the town of Haven has been destroyed. Cause and Effect? No one knows, but official policy of Britannia is to have nothing to do with blackrock.
8. Miscellaneous other information on blackrock
After the original blackrock pillar exploded in Terathan Keep, blackrock appeared throughout Britannia in other ways. Small pieces were found on the ground in the wilderness, and later on, several motherlodes of blackrock were discovered in the Lost Lands. At the motherlodes blackrock pieces could be dug up by players with no mining experience, at the risk of being attacked by Blackrock Elementals, Toxic Oozes and Nether Vortexes. Also at the motherlode areas a strange skill effect was seen, that of the player being able to raise skills with little effort. At the current writing blackrock cannot be acquired at the motherlodes, nor can improved skill gains be made. All of the information is this section is historical only, blackrock can currently only be acquired by mining.

Forum Veterans please feel free to correct me/add information in replies. Thanks!
1. What is blackrock?
Blackrock is a substance that first appeared in Britannia during the war with the Ophidians (2006). A strange pillar appeared in the bottom of Terathan Keep, which when destroyed showered pieces of blackrock in the dungeon.
2. What is blackrock good for?
Blackrock is the reagent for the Armageddon spell. Armageddon, when properly cast, would result in the annihilation of all life on Sosaria. So far, no one has been able to properly cast it. Any Mage or Necromancer of at least GM skill can attempt to cast Armageddon. To do so, you must possess a piece of blackrock, which you place on the ground near you. Then you say the following words of power: vas kal an mani in corp hur tym. If you're unsuccessful, you'll get a message that "you feel uneasy." If you're successful, one of several things can happen:
__a. You'll wave your arms a little as if casting a normal spell (if your hands are free and you are not mounted on a pet).
__b. The blackrock will explode, blowing you several tiles away, and damaging you.
__c. The blackrock will explode and kill you. Your body parts will be scattered around the area, and your possessions will be in a backpack near the torso of your body.
__d. A Wisp will appear and attempt to communicate you. It will even follow you around for a short while, before departing.
3. Where do I find blackrock?
Currently the only way to acquire blackrock is to dig up a piece while mining. To dig up blackrock you must be a GM miner, either naturally or with use of Blacksmith Gloves of Mining, which means you can dig blackrock with 95 mining if you have the Ringmail Blacksmith Gloves of Mining. Blackrock can be found in any normal mining spot, will drop into your backpack along with a message that you have found a piece of blackrock. This message is similar to the message you receive when you dig up a Mondaine's Legacy gem. Be aware that blackrock is a rare drop, and you will not find a lot of it. You can improve you chances by mining in Felucca, with all the usual cautions in effect. Mined blackrock is very small and hard to see in the 2d UO backpack, so you may not realize you have a piece.
4. I dug up a Blackrock Elemental! Help!
Blackrock Elementals are bad news. The developers designed them to deter script mining, and also to provide a penalty for daring to dig for blackrock. Blackrock Elementals look like Shadow Iron Ore Elementals, but are titled A Blackrock Elemental in red script. The Blackrock Elemental is very close to unkillable, is as fast as a Paragon, has a huge number of hit points and powerful hit point regeneration. They suffer no damage from pets, spells or summons creatures, and reflect all damage at the rate of 50%. If you are near a town they can be lured there and guard whacked (I speak from experience here). Otherwise it is best to lure them away from your corpse so that you can gather your belongings.
5. I cast Armageddon, and now I hear voices!
You are infected by blackrock. As of this writing, what this means to the infected character hasn't been revealed by the developers, but it results in a couple of phenomena:
__a. You begin to "hear voices" (text messages in your play window). These range from greetings (Good Morning!) to incitement to murder (Kill them! Kill them all! Tear them to pieces!).
__b. You begin infecting creatures, NPCs and monsters nearby with Blackrock sickness. This results in the creature turning red, becoming more powerful, and attacking players on sight. Any creature that has a chance of dropping a treasure map will, when infected by blackrock, have a chance to drop a special treasure chest.
6. I just infected a cat and I didn't even cast Armageddon! What gives!
It is possible to infect creatures with Blackrock sickness simply by carrying a piece of blackrock in your backpack. If you don't wish to infect creatures, put the blackrock in storage.
7. Who are these "Traders" I've heard of that give rewards for blackrock?
Mysterious people in black shrouds titled "A Trader" appeared in the town of Haven recently, offering incredible rewards for blackrock. These ranged from Mondaine's Legacy Peerless ingredients and gems, to Doom Artifacts and Tokuno Treasure artifacts, to upper level Runic Hammers and Ancient Smithy Hammers. The Traders have since disappeared, and the town of Haven has been destroyed. Cause and Effect? No one knows, but official policy of Britannia is to have nothing to do with blackrock.
8. Miscellaneous other information on blackrock
After the original blackrock pillar exploded in Terathan Keep, blackrock appeared throughout Britannia in other ways. Small pieces were found on the ground in the wilderness, and later on, several motherlodes of blackrock were discovered in the Lost Lands. At the motherlodes blackrock pieces could be dug up by players with no mining experience, at the risk of being attacked by Blackrock Elementals, Toxic Oozes and Nether Vortexes. Also at the motherlode areas a strange skill effect was seen, that of the player being able to raise skills with little effort. At the current writing blackrock cannot be acquired at the motherlodes, nor can improved skill gains be made. All of the information is this section is historical only, blackrock can currently only be acquired by mining.