Bobfergusonite

Bobfergusonite occurs as equant anhedral single crystals up to in size or as nodular aggregates of few crystals. The mineral varies in color from green-brown to red-brown. Bobfergusonite has been found in association with alluaudite, apatite, beusite, fillowite, and triplite. Bobfergusonite is a primary mineral that occurs in the intermediate zone of manganese and fluorine enriched granitic pegmatites. ==Structure==

Bobfergusonite has a layered crystal structure topologically identical to that of alluaudite and wyllieite but with differences in the ordering of metal cations. The two types of layer alternate along Y. One layer consists of chains of metal cation octahedra cross-linked by phosphate tetrahedra. Within the chains metal cations are ordered M3+–M2+ in a similar fashion to wyllieite. However, the structure of bobfergusonite is distinct by the presence of Al and Fe3+ ordering between chains. ==History==

Alan J. Anderson discovered large brown crystals in a granitic pegmatite at Cross Lake in Manitoba. Study by electron microprobe and X-ray diffraction identified it as a new mineral related to the wyllieite and alluaudite groups. The mineral and the name bobfergusonite were approved by the IMA Commission on New Minerals and Mineral Names. ==Distribution==

, bobfergusonite is known from the Nancy pegmatite in Argentina and the Gottcha Claim in Manitoba, Canada. The type material is held at the University of Manitoba and the Royal Ontario Museum in Toronto. ==References==