[TheForge] Fitchburg Furnace

[Hufford, David]

I recently visited the national historic site of the Fitchburg (Red River) Furnace located near Ravenna Kentucky.  It's a well-preserved beautiful double furnace from 1869, which produced iron for the railroad.  Scattered around the site were lots of 'glass' rocks; green and other colors, some appeared to have slag on one side.  Is this glass a byproduct of the smelting process?  If so, does it derive from the limestone flux or from the iron ore?  Any information on this would be appreciated.

David Hufford
Richmond KY