We know that Blackmoor is a "special" magic region (it attracted plenty of wizard at the colonization phase, etc. etc.), we have a hint that the source of magic can be related to some geological features (black shiny stones? dragonstones? maybe? maybe is just a red herring?).
What I don't know is the root cause why Blackmoor is such a special place (i.e. if it's for the black stones, why do we have more black stones in Blackmoor than in other parts of the world? How did the black stones get created right here?).
Any idea / guess?

There are few fan theories on this.

I believe Thorn's Blackmoor refers to this special mineral as Utherite.

My own theory is that Blackmoor was visited by an Old One, as a result of the failed . It is the power of this Old One that was fused with the very rock of the peninsula Castle Blackmoor was later built upon.


The idea of an Old One having visited Blackmoor is derived from certain hints in Dungeons of Castle Blackmoor. The presence of a Blackball-like creature in the Dungeon for instance.

Also, I like the idea of this Old One being an analogy for Dave...


So going with either Rob's theory or mine, Blackmoor would be pretty rare in posessing this mineral. On the other hand, if Blackmoor was dramatically destroyed in an explosion, that would scatter this mineral all over the world, wouldnt it? 8)

I think Rob was playing more with that idea...

-Havard

Thorn's Blackmoor posits that the foundations and spire upon which the castle is built are magical-warping stone called Andahar Onyx. It is thought that it's properties stem from the Blackball in the bottom of the Blackmoor dungeons causes the warps and folds In the magical fields and ley lines in the North.

Sorry, I'm not sure I got your idea: the Blackball is cause or effect of the magic?

The stone itself is magical, but its properties are skewed by interaction with the blackball.

Right, but the stone itself is magical for some special reason or it's just by sheer "luck"?
According to most sources, Blackballs tend to slip through [existing] tears in the fabric of reality, rather than producing the tears by themselves...

Personally I just go with what the books say - that the Black stone and the soil derived from it are magical/magic enhancers. You don't need to look for any roots deeper than that if you don't want to because explanations have to stop somewhere.

I can see your point... maybe it's just an obsessive "root cause analysis" approach I'm getting from my job... :?

It depends on your preferences. Some prefer a more bare bones take on Blackmoor and that is definitely valid. :)


What I like to do is to dig up different setting references and try to weave a story between them. This doesn't make that a more true version of Blackmoor, but I find that it is a great exercise in creativity, and also it tends to provide lots of adventure ideas, while staying within the common frame of reference which is published material.

-Havard