User blog comment:High King Ithilion/New Map of Middle-earth!/@comment-25012056-20160624131630/@comment-26149161-20160624134933

According to the Atlas of Middle-earth it's volcanic rock. I say we go with that. Plus, if we make the Whites higher (they were the highest in the West) there can be more snow.

Ithilion, Discussions Moderator (Auta i lome) 13:49, June 24, 2016 (UTC)