New Mexico Mineral Symposium — Abstracts

Mineral collecting in Michigan's Iron Country can be interesting and rewarding for the persistent collector. Iron Country for the purposes of this presentation will consist of the four central counties of Michigan's Upper Peninsula (Marquette, Baraga, Dickinson, and Iron). Iron mining in Michigan's Upper Peninsula began in 1845 at the Jackson mine near the present town of Negaunee. From 1845 to the present, 247 iron mines were to operate on what was to become the Marquette Iron Range. The Menominee Iron Range in Dickinson and Iron Counties also had many iron mines, the last of which operated up until 1981.

Many of these mines left open pits and poor rock piles and dumps that beckon to the collector of minerals. Hematite, goethite, pyrite, calcite, barite, and manganese minerals are commonly found in these areas. Micro crystals of apatite, rhodochrosite, dolomite, sammetblende goethite, filiform pyrite, chalcopyrite, and gypsum can also be collected. Chloritized garnets from the Michigamee mine are distinctive and widely recognized.

Marquette County had the only operating gold mines in the region. The Michigan gold mine, north of the town of Ishpeming, produced the best specimen gold around the turn of the century, but the old dumps still produce free gold. The Ropes gold mine operated intermittently between 1881 and 1990 and produced dumps that can be accessed with permission. Specimens of antigorite, chrysotile, and green talc with dolomite are readily obtainable along with micro crystals of pyrrhotite, goethite, and even galena. Massive tetrahedrite and occasionally free gold can also be collected. Quartz veins and pegmatites in natural outcrops and mine prospects in the area have yielded some diverse minerals. Britholite-(Y) and xenotime-(Y) from the Black River pegmatite and chalcocite, azurite, and wroewolfeite from the Captain Daniels' "mine" are examples.

World class specimens of pyrolusite and rnanganite have come from the Taylor mine in Baraga County, and the location is still accessible. Recently, micro crystals of rhodochrosite and barite were found in the area. Marble quarries in Dickinson County have yielded excellent tremolite specimens and micro crystals of hematite, goethite, and marcasite. The now-closed (1981) Groveland mine near the town of Fekh has produced excellent calcite crystals along with pyrite, marcasite, and ferroan dolomite. Micro crystals of chalcopyrite are common.

Collecting on the mine dumps of Iron County will produce minerals similar to those found in Marquette County, but historically, the mines of Iron County have turned up some exceedingly rare minerals. The Chicagon mine near Iron River was until recently the only known location for seamanite, a hydrated manganese phospho-borate. The rare mineral shigaite, a hydrated manganese aluminum sulfate, has been found from two mines near Iron River. Attractive micro crystals of rhodochrosite have been collected recently from the dumps of the Chicagon mine.

Mineral collecting in Iron Country can be challenging due to vegetation, insects, and the climate, but new and exciting mineral discoveries are being made, even today.