Kings Under the Mountain

All seven of the artifacts are items from the Dwarf tier in archaeology.

Common tier:
Moltenfist's Jeweled Goblet
Ironstar's Petrified Shield
Winged Helm of Corehammer
Mithril Chain of Angerforge
Skull Staff of Shadowforge
Warmaul of Burningeye
Spiked Gauntlets of Anvilrage

If you're coming to this achievement for housing decor and you thought, "Oh, this sounds like a quick 2-hour job!" Do not even start this achievement. I'm 14 hours in, end of day two. I've been 1 solve away for 8 of that. I'm up 1 new mount, 4 new pets (3 dupes), and 5 new toys. I've deleted the same "Rare" Hearthstone Artifact 2 times. I genuinely have carpal tunnel. If you want easy decor, please just turn around. Unless you REALLY, REALLY, REALLY want the brazier, this isn't worth it. I'm not even sure [item=64368] exists anymore.

Edit: 19 hours, per a stream recommendation, I have stopped digging actual Dwarf sites and I've started digging Mantid sites with the maps and Dwarf boxes from Brann. If you don't know, he's at the Seat of Knowledge and he sells a bundle of items to make all of your sites Mantid for 24 hours. They're all very close together and much smaller. Then you can crate the Artifacts to trade for Dwarf fragments. Even though you get fewer fragments per digsite, it's much faster fragments than flying all over the Eastern Kingdoms doing Troll digsites.

Edit: After ~26 hours, end of day 4, I think I'm giving up. Seeing the 150-fragment Hearthstone appear as my next solve for the 4th time has broken me. I'm so sick of archaeology.

"Three Rings for the Elven-kings under the sky, Seven for the Dwarf-lords in their halls of stone, Nine for Mortal Men doomed to die, One for the Dark Lord on his dark throne, In the land of Mordor where the shadows lie..."