Garnierite and Limonite pseudomorph after Millerite (RARE locality specimen)

Item Description

An INCREDIBLY rare locality specimen from Mabilikwe Hill, in South Africa, a nickel deposit which according to mindat.org has not actually been formally mined, and specimens have only been collected from exposed outcrops. This is the ONLY specimen we've ever seen from the locality, and we couldn't even find another for comparison anywhere online. The label accompanying the piece states that it is "Garnierite" (green) and Limonite pseudomorphing Millerite. Let me start by saying that Garnierite is not a species, but rather a catch-all term for various nickel-bearing minerals, namely Népouite, Pimelite and Willemseite. To further complicate the matter, Pimelite is no longer a valid species as of 2006, and neither Népouite, Pimelite nor Willemseite have been reported from Mabilikwe Hill. Of the green nickel-bearing minerals that are confirmed from this locality, the likely candidates present on this piece would be either Gaspéite, Otwayite or Glaukosphaerite, and perhaps a combination of two or more. With that said, you can see there are dozens of thin prismatic Millerite "needles" on the specimen which have been replaced by pastel green to yellow-green colored secondary nickel mineral(s), along with a bit of rusty brown Limonite, on a bit of matrix. A really interesting and unusual specimen, from a remarkably rare locality. If you collect rarities, pseudomorphs, oddball locality pieces, or you just enjoy "mysterious" specimens, this is a great opportunity to pick up something that is non-existent on the market today. From the collection of William ("Bill") (1927-2006) and Anne (1928-2021) Cook of Cleveland, Ohio (#12,521) with a label from Mineralogical Research Company (Gene and Sharon Cisneros). Bill and Anne were actively involved in the mineral world for many decades. Bill was a PhD geologist, and Anne was a mathematician, and they both were very serious mineral collectors. Bill served for many years as adjunct curator of mineralogy at the Cleveland Museum of Natural History, and Anne was inducted into the Micromounters' Hall of Fame on October 12, 2019. Both Bill and Anne, at various times, served as president both of the Mineralogical Society of Cleveland and of the Micromineral Society of the Cleveland Museum of Natural History, and Anne was inducted into the mi The rare barium lithium beryllium phosphate Wilancookite was named in their honor in 2015.