Mineral Collection of Richard Gunter

OXIDES

HEMATITE Fe2O3



Location: Phoenix Mine, near Grand Forks, B.C.

Specimen: 4.5 cm x 4.5 cm specimen of skarn with a 2 cm cavity lined with 1 mm masses of Malachite, 1 mm rusty brown Andradite Garnet, 1 mm colourless “cactus-style” Quartz crystals and several 2 to 5 mm thin non-edged Hematite “Iron Rose” that are not even slightly magnetic. The matrix of the cavity is Quartz and massive Andradite. The Quartz has small crystals growing from the prism face of the main crystal. This sample was not filled with secondary Calcite, all the cavities in the porous Andradite skarn were open and crystal lined. The occurrence of Malachite seems to indicate the cavities were not Calcite filled. The Fe-oxide crystals are non-magnetic and are still Hematite.

There is not enough detail on the Phoenix Mine mineralogy to know the setting of the Hematite vs Magnetite after Hematite parageneses. Ettlinger and Ray (1987) in their study of the mineralogy of the gold-copper skarn in British Columbia mentions the Specularite-Chalcopyrite-Calcite paragenesis in veins cutting the skarn, with a small photo of a sample similar to this one. They do not mention the Magnetite after Specularite pseudomorphs but do mention Magnetite and Hematite associated with the Chalcopyrite-Pyrite ore.

Mindat.org website has a photograph of an “iron rose” from the Phoenix Mine, along with this sample. The caption says that these are very rare. They look like the smaller “iron roses” on this sample. The larger roses resemble the Swiss type. The Wienrich commercial website (November 17, 2004) had a sample on auction that was listed as Andradite Garnet and Pyrite that appeared to be from the same paragenesis.

Locality Library: Phoenix Mine; the sample was personally collected August 1984 from the dumps of the mine. Ettlinger and Ray (1987) did a study on the mine that is in the computer. A matching paragenesis on the specimens can be seen from hand samples. Samples from this mine on commercial websites are very rare. This sample and the others from the find have been posted to the Phoenix Mine web location in Mindat.org.

The Minfile program of British Columbia says: The ores of the Phoenix area are almost exclusively the result of limestone alteration. The extensive deposits of low grade copper ore, which have given rise to the mining industry at Phoenix, occur in mineralized areas of the Brooklyn limestone, which have all the characteristics of metasomatic replacements. These replacements are composed essentially of chlorite-epidote skarn rocks with variable amounts of garnet, calcite and quartz, accompanied by blebs and disseminations of pyrite, chalcopyrite, magnetite and specularite. The skarn and copper minerals are localized in a band of impure limestone above a well-defined footwall argillite. The thickness of mineralization varies from a maximum of 60 metres to less than 1 metre at the limits of mining. The ore beds are generally inclined downward to the east, but dips vary and a series of north-south faults have produced irregularities