Weinebeneite, CaBe (sub 3) (PO (sub 4) ) (sub 2) (OH) (sub 2) . 4H (sub 2) O, a new mineral species; mineral data and crystal structure

Weinebeneite occurs in small fractures in a spodumene pegmatite at Weinebene, in high-grade metamorphic rocks of Koralpe, Carinthia, Austria; it is associated with fairfieldite, roscherite and uralolite. It forms colourless, platy crystals < or = 0.1 X 0.3 X 0.5 mm surrounding rosettes of xenomorphic weinebeneite < or = 20 mm; H. 3-4, D 2.15 g/cm (super 3) (D (sub calc) 2.17 g/cm (super 3) ); alpha 1520, beta 1.520, gamma 1.530, 2V (sub gamma) 10 degrees, gamma:c 42 degrees in acute beta . Indexed powder XRD data are tabulated; strongest lines 2.513(100), 3.421(70), 5.92(60), 2.959(60), 4.33(49) Angstrom ; a 11.897, b 9.707, c 9.633 Angstrom, beta 95.76 degrees ; space group Cc; Z = 4. EPMA, AAS and structural analyses lead to the idealized formula CaBe (sub 3) (PO (sub 4) ) (sub 2) (OH) (sub 2) bullet 4H (sub 2) O. Weinebeneite is a framework beryllophosphate with Ca and H (sub 2) O molecules in the cavities of the structure. The Be- and P-tetrahedra share corners, forming a layer of four and eight rings. Two superimposed 4.8 (super 2) 2D nets [A.M. 63-960] oriented (100) and related by translation in b/2 are connected by additional Be tetrahedra giving a framework with an unusual arrangement in which five tetrahedra in two three-membered rings share a tetrahedron. Ca is located in channels [001], coordinated by three O atoms of the framework and four water molecules, one of which displays apparent positional disorder over two sites.