Earth elemental Earth Glide ability within man made structure

[LucyG92]

Can an Earth Elemental burrow through stone if it is part of a man made structure such as a ruin? Dungeon walls made of stone, that sort of thing?

[Saethori]

Earth Glide works on "Stone, dirt, or almost any other kind of earth but metal". There is no provision about whether the stone needs to be natural, so earthen bricks work fine. It's only metals that impair the elemental's ability, as well as whatever rare corner cases of earthen materials warrant the "almost any". (Gemstones?)