Well, it came about from several events.
You can cast the Spell of Armageddon using it. But the spell is only a poor example of "armageddon", as it explodes and can do enough damage to kill you.
You place a piece on the ground and stand next to it, and say:
Vas Kal An Mani In Corp Hur Tym.
As far as I know, you have to be a highly skilled Mage to make it work, with a chance of success. If it fails, you get a message something like "you feel uncomfortable". If it works, it explodes and you take damage. Sometimes enough to kill you and leave you as body parts. (There's a backpack also that functions as your corpse, with your items.)
It used to blow your ghost back a couple of steps too, but they removed this. It allowed people to get into places you normally can't. Someone here used it to get into the locked room in the lower levels of the Terranthan Keep and explore it as a ghost, but found nothing interesting.
Casting this spell attuned that player to some other dimension (presumable the Void?), and they started hearing voices. Short comments like "Hello", "You are not finished yet", "Kill them, kill them all". There were also a few things that sounded quite friendly. This persisted for a long time, but eventually just went away. Maybe an event caused this, I don't know. There was a lot going on back then under Draconi, too much to get into here.
This spell also can, on a small chance, summon a special "Blue Wisp" that asks you for a "dense source of knowledge" and will reward you with a trade of knowledge. Most think this doesn't work anymore, but about 2 months ago I was successful in this summons. No one has figured out the right thing to give it, as far as I know.
It originated from an event about Ricardo and the stealing of the Ophidian's relic, the Artificed Scion (?), by Ricardo. The special Ophidians that assaulted our lands had built some sort of Blackrock device in the Terranthan Keep (which they also assaulted because they had captured Ricardo and held him prisoner there, which is a secret place that you can still get into.
When we attacked these Ophidians in the Terranthan Keep, where their blackrock construction was, we eventually destroyed the construction, causing it to explode. That left about 20 "A Piece of Blackrock", in each incidence (shards and Fel/Trammel). These pieces are limited and more rare, and they are different only in the name, lacking the "small".
After that, the explosion also caused the "small pieces" to start spawning all over the lands, and they never decay. They no longer just spawn like that. Now they are a random drop when a GM mines. And there's so much of it that many just drop it where they got it. You can make runs along mining areas and sometimes find quite a few pieces.
There are also bigger pieces that look like the "rocks" that are a semi-rare, only black. They come with various weights. These were mined initially from the spots in the Lost Lands. I don't know if miners can get any of these.
Blackrock does not decay. You can drop a piece anywhere, and if no one picks it up, it stays there.
It can still be used to cast the "Armageddon" spell, and still sometimes explode, but you don't start hearing voices.
However, there are a couple of other uses that are still in effect.
For one, some event MOBs take damage equal to half of their current HPs, if you speak those words while carrying a piece and are close enough to them. The Blackrock is used up for this. I'm not sure we'll see anymore of those sorts of MOBs, there were only 2 or 3 I think.
You can also carry a piece, and this allows you to "defeat" the special protections of the Dark Wisps, so you can do damage when otherwise you couldn't.
And that's a "quick" rundown.
I may be a little off, here and there. Others can correct me if so.
