If you read any of the books about Raven Rock or talk to some of the villagers, they will tell you that the ebony in the Raven Rock Mine has all been dug up. What I found interesting is that when you go in there you find several spots where they use the same texture as they do for an ore vein once it has been exhausted. This is something that would be easy to overlook, but the artists put that detail in anyway. Nice touch.

Okay.

It is quite pleasant to notice the developers' attention to such a small detail in an expansion such as Dragonborn. It is not the picture as a whole, it is the individual brush-strokes that make up the value of the portrait.

I feel stupid for trying to mine those now XD

I thought the game was glitched

A comment such as this is wasteful and not the least bit constructive. Keep your arrogance to yourself.

Lol. I thought it was a bug that I couldn't mine those!

I came to this conclusion myself. I thought it was a nice touch.
Now someone explain the hexagonal rock formations to me.

Should be common knowledge by now that the Ebony Mines of Raven Rock are empty. (An NPC in Oblivion talked about working at Raven Rock and how the Ebony ran out).

Glad Bethesda remembered this and added the little detail.

Although i am mostly a technology person i think i may know.
It is called columnar jointing. http://3.bp.blogspot.com/_tGHzOEp3UKA/TKzAQE2QoaI/AAAAAAAAB3o/1CpT-RPqozA/s1600/Encyclopedie_1768_Giants+Causeway.jpg. They form as a result of the contraction of a cooling solidified lava flow(most likely a basalt).
This would tie in with the lore of the eruption of red mountain.

Talk about attention to detail.

Ohh, I was wondering why it looked so familiar. The Giant's Causeway in Ireland; I've seen that before. The fact that it can be tied into Red Mountain's eruption just makes it more awesome.