I'm running the Giantslayer AP in which all the PCs are dwarves. As such, I'm trying to tie as many elements of the campaign as I can into dwarven history and tradition of Golarion. One notion I had was to replace the swamp-dwelling Council of Thorns' druidic order with a stone & crystal mystery-cult centered around the dwarves' ancient subterranean origins and their mystical ties to the element of earth. Instead of having reincarnated as Will-o'-wisps, the dwarves of the mystery cult instead transformed themselves into earth elementals to safeguard their vualt. I'm going to change the interior of the Vault of Thorns in the second module from a lush woodland-themed pocket plane to a giant hollow crystal geode with with a giant fungi forest inside.
I was thinking that the lone surviver of the "Council of Thorns", now a venerable dwarf known only as Silverbeard, may try to initiate the PCs into his largely extinct order. To that end, I'd like to hear some suggestions for fleshing out the possible lore and doctrine of an elemental earth based cult as well as giving it an appropriate name which the party could adopt as their own if they're so inclined. Suggestions welcome.
Brothers of stone.
Crystal, Gem, Ore, Metal, Stone, Sand, Metal, Earth, Soil, Cave, Tunnel...
The Earthwyrm Mysteries? Crystal Striders? Sky Seekers? Crystal Gazers?
Could they seek out magic fungi, veins of crystalline materials for crystal balls, endure intense physical labor, forge a new kind of metal or weapon or armor or tool, sail iron ships on seas of sand or magma, gain immunity to a toxin, survive the strange forces (radiation) of the deep earth, dig a new tunnel, create a sand painting, navigate a maze, outwit a sphinx.
You might want to figure out this Mystery Cult's relationship to the Dwarven Quest for the Sky, which was all about getting the dwarves onto the surface.