Biotite (rare locality specimen)

Item Description

For many years, Biotite was a valid species, but it has recently been redefined, and the entry on mindat.org states, "The name is most commonly used generically (in the field or petrologically) for any unanalysed or incompletely analysed dark-coloured, Fe-rich micas, including Annite, Fluorannite, Tetra-ferri-annite and Siderophyllite." With that said, I've seen these specimens specifically labeled as Annite, though I cannot say for certain if that's the case with this piece. Regardelss, this is a fantastic display specimen of this hard to find material from Topsham. The focus of the specimen is the big, fine quality, well-formed, lustrous, deep brown-black colored hexagonal crystal of "Biotite" measuring 6.1 cm, aesthetically sitting on feldspar matrix. A few additional "Biotite" crystals can be seen on a few spots on the specimen. The piece sits beautifully on its own without the aid of a base or clay, allowing the excellent Mica crystal to stand up perfectly. If you collect minerals of New England or worldwide Micas, or you have a suite of Maine minerals, do not miss out on this showy and beautiful piece.
From the collection of William ("Bill") (1927-2006) and Anne (1928-2021) Cook of Cleveland, Ohio (#12,091). This husband and wife duo 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.