Merchants argue about the qualities of metals in the Guild Halls of Iltkazar, far to the south of Menzoberranzan in the Underdark, beneath the surface realm of Calimshan. "While Iltkazarn miners are quite capable of mining common ore such as copper, iron, gold, silver, and tin, they excel in discovering and working with rarer metals." (Michael Collins, Drizzt Do'Urden's Guide to the Underdark by Eric L Boyd, TSR, 1999)
This also might represent the Hall of Runestones temple described on the next page, but it was printed directly within the paragraph on mining and ores, and I know how much Tumblr likes ancient arguments about ores inscribed on tablets.