Stibiconite / Romeite pseudmorph after Stibnite

Item Description

For many years, these specimens were identified and labeled as Stibiconite pseudomorphs from the Real de Catorce Mine in San Luis Potosí, Mexico. The entry for this locality on mindat.org states that the majority of these specimens actually were found at the San José Mine which lies 10 km south on the west flank of the Sierra de Catorce at Estacion Wadley. The actual Real de Catorce Mine was a well-known historic locality, and probably easier for people to recognize and identify specimens. Then we have to get into the classification of Stibiconite as a species. The exact entry on mindat.org states, "Stibiconite is not, as yet, a discredited mineral and is classified as 'Grandfathered' by the IMA. Full characterization of 'stibiconite' specimens is difficult, requiring full quantification of the oxidation states of Sb for complete characterization to determine whether it is a Sb3+ dominant romeite species or a new phase related to known synthetic phases Sb2O5 · 1-3H2O which have been reported to have a pyrochlore structure and contain no Sb3+ (Christy & Atencio, 2013)." So we have in turn labeled this piece as being Stibiconite / Romeite pseudomorphing after Stibnite, which as of the time of this listing is probably the most accurate way to identify them.
This specimen is a wonderful example of these beautiful and well-known pseudomorphs featuring light powdery yellow Stibiconite / Romeite which has completely replaced a prismatic "spray" of pre-existing Stibnite crystals, free of matrix. The largest individual crystal measures about 4.6 cm long. The main crystals atop the specimen are in superb condition, but a few of the smaller accenting crystals towards the base of the piece are contacted. Overall it's a very showy and highly displayable example of these now fairly hard to find pieces that date back around the 1960s.
From the collection of Gary and Terry Butts of Livermore, Colorado. This husband and wife collecting duo were childhood sweethearts, and have been together since they began dating as teenagers growing up in East Des Moines, Iowa in the 1950s. Both of them had an early interest in the hobby thanks to the fact that Terry's parents had a keen interest in lapidary, which sparked an interest in rocks for both of them. Gary and Terry were featured in an article in the Des Moines Register on Feb 4, 1962 (see photo in this listing) highlighting their interest and prowess in the hobby as youngsters. Gary traveled to various localities around the US as a teenager with his father (who worked in the tin industry), to personally collect specimens. He then attended the School of Mines in Golden, Colorado and graduated in 1967 with a degree in extractive metallurgical engineering. We went to work for Duval Corp at the Esperanza Mine south of Tucson, Arizona and then work for Cyprus Mines, Hazen Research, Pincock, Allen & Holt and the Colorado School of Mines Research Institute. His final job was in the mineral and environmental division of Intertek Testing Services of London, which owned the Canadian mineral testing company, Bonder Clegg. Gary's various jobs allowed him to travel the world and build his collection by buying a lot of specimens in person when they were coming out of the ground. Additionally, Terry's uncle was a miner in Creede, Colorado and later owned a rock shop which supplied Gary with specimens from the area. The specimens in this auction represent what Gary and Terry considered the "cream of the crop" of their collection.