The type sample of rossmanite. Pink 2.5 cm crystals in lepidolite. (photo credit: Jan Cempiŕek)
Rossmanite was found in a lepidolite subtype pegmatite dike that is the type locality of lepidolite mica. It occurs with other members of the tourmaline group (schorl, elbaite, dravite, foitite).
X(0.57Na0.43) Y(Li0.71Al2.17) ZAl6 (Si5.92O18) (B2.92O9) [(OH)3.83F0.10O0.07]
where X, Y, and Z refer to the X-, Y- and Z-sites, respectively.
The type sample:
The type sample, illustrated above, resides in a museum case in Brno, Czech Republic. It is the sample in the bottom front row, second from the right side.
Another sample from this locality is pictured below
The analysis of this specimen indicates rossmanite. It dates back to the late 1800's to the early 1900's.
Information and the image are from Alan Guisewite's website:
Selway JB, Novák M, Hawthorne FC, Cerný P, Ottolini L, Kyser TK (1998) Rossmanite, (LiAl2)Al6(Si6O18)(BO3)3(OH)4, a new alkali-deficient tourmaline: Description and crystal structure. American Mineralogist, 83, 896-900.