Well I was out with rockhounds but we were collecting fossils, hematite and goethite on the waste piles around Hibbing. Our tour guide was both a rockhound and former Hull-Rust miner. We visited the Hull-Rust mine and the Hill-Annex mine. Our guide told us of the time he dodged a 26 pound rock flying into his Calumet school yard as a result of blasting in the Hill-Annex mine.mr greenjeans said:one thing we do around here is search for Superior agates.
The rocks I chose are rounded noduals of shiny black rock that rusts very fast and gets a red iron oxide coating. I think this is the same stuff they make jewlery outa but I wonder why it doesn't rust in the trinket stores. Speculation amoung the rock club was that these samples were from the Cambrian layer and were rounded by wave action. They claimed this ore was more than pure enough for smelting. Mixed in with the same till pile was plenty of goethite but it was mostly found in thin layers on sharper shards of rock. The goethite didn't show the same propensity for rusting that the hematite does. I really liked the look of these rocks when black and shiny but the rusting kinda dimmed my enthusiasm for aquascaping with them. I have them in a bucket now to see how they behave submersed.pineapple said:In what form is the hematite (Fe2O3)? Granular? Colouration?