Board Thread:Suggestions forum/@comment-34204318-20180322053453/@comment-33185350-20180323055005

For the sake of this discussion I think it’s important to note exactly what the book describes. Here’s Orthanc:

“It was fashioned by builders of old, who smoothed the Ring of Isengard, and yet it seemed a thing not made by the craft of Men, but riven from the bones of the earth in the ancient torment of the hills. A peak and isle of rock it was, black and gleaming hard: four mighty piers of many-sided stone were welded into one, but near the summit they opened into gaping horns, their pinnacles sharp as the points of spears, keen-edged as knives. Between them was a narrow space, and there upon a floor of polished stone, written with strange signs, a man might stand five hundred feet above the plain.” - The Two Towers

It’s interesting to note how accurately the movies depict the tower described here (with a few minor differences). Aside from that, however, we can notice several key points.
 * No bricks are mentioned.  It appears to be one solid piece of rock.
 * It’s clearly beyond the technology of current builders.
 * The stone is described as black, gleaming, hard, and many-sided. It really does fit with obsidian, aside from being hard.
 * ”Keen-edged as knives” is a distinctive quality of obsidian as well.

Later on, there is a description of the Ents’ attack on Orthanc itself:

“Many of the Ents were hurling themselves against the Orthanc-rock; but that defeated them. It is very smooth and hard. Some wizardry is in it, perhaps, older and stronger than Saruman’s. Anyway they could not get a grip on it, or make a crack in it; and they were bruising and wounding themselves against it.” - The Two Towers


 * This stone is remarkably strong. Not only does it have no cracks or chinks for Ents to pry it apart, but it also resists the brute force of massive stone slabs being hurled against it.
 * It seems likely the Ents would have pried it apart if it consisted of bricks.
 * It appears there may be a magical explanation for the indestructability, or at least the Hobbits speculate so (even though their knowledge of such matters is unreliable).

Moving on to Minas Tirith, the book describes the outer wall:

“For the main wall of the City was of great height and marvelous thickness, built ere the power and craft of Númenor waned in exile; and its outward face was like to the Tower of Orthanc, hard and dark and smooth, unconquerable by steel or fire, unbreakable except by some convulsion that would rend the very earth on which it stood.” - The Return of the King


 * This confirms a lot of the previous observations. If it’s unbreakable as described it clearly must be a single piece, that would only crack under a phenomenon of seismic scale.
 * It’s indestructibility is due both to the “power and craft of Númenor,” meaning some of it seems to be (lost) skill to make the material and some of it seems to be magic.
 * ”Unconquerable by steel or fire” clearly indicates even the most powerful battering rams (or pickaxes) would not be able to mine through it.

In conclusion: I think that obsidian would be a good fit. While this stone is clearly uncraftable with current technology, Minecraft obsidian is already craftable and fits the appearance and blast resistance. However, it’s not completely unbreakable. There’s an easy fix to this: “This land is under the protection of an ancient power.”  It seems to fit with the description, and is already a mechanic in game.

There are a few problems with this solution, however. Firstly it would just be weird to break a banner them be able to mine away Orthanc. Perhaps the protection could be always present, not just applicable to a banner? Next, the protection should only apply to obsidian itself, not other blocks in the area (bricks, doors, dirt, stone...) to show this stone is remarkable. Finally, this stone really shouldn’t be craftable. In my opinion players crafting obsidian isn’t such a major problem as long as the stone in the structures is still set apart by banner-type protection tied to the location.