Board Thread:Suggestions forum/@comment-34802087-20180224102101/@comment-33185350-20180224145529

I’d love to see better geology in a game so focused around mining. Generic “stone” is really not a thing. Andesite and granite pockets as present in later versions help but still don’t solve the problem. In reality lots of geological deposits are flat and widespread, stacked on top of each other. Sandstones, mudstones, shales, etc. are pretty common. Granite would be deeper down. Basalt would also be a good widespread rock (being dark in color and volcanic in origin it actually seems to me like Mordor Rock is basalt). Limestone in my opinion would be a really good generic stone in many middle to higher areas of the underground, with a slightly lighter color and more caves but less ores. All the mountains should be made of granite, except the (coming soon) Jungle Mountains which would be made of limestone. Granite should have a grey texture like the current one but more granular, with the pink variety being less common.

But that would really be a lot of work into world generation for something most people probably don’t care about. I don’t think it would be worth it.

Also it’s hard to say how different Middle-earth’s geologic history is from ours. Perhaps no large-scale sedimentary layers like limestone would be present. I already find the Chalk deposits doubtful, as chalk is laid down when diatoms (small sea creatures) die and leave their microscopic shells behind.

@AlteOgre: My Roots of the Mountains suggestion actually discusses adding various underground sub-biomes (albeit in a separate deeper dimension). There I also recommended white and black marble as new types of stone. Perhaps something similar here?