Paulkerrit a earlshannonit z Dolních BorůČlánek v PDF
Paulkerrite and earlshannonite from pegmatite near Dolní Bory (western Moravia, Czechoslovakia)
Assoctated with secondary Fe-Mn phosphates from pegmatite near Dolní Bory, two additional ones – paulkerrite and earlshannonite – were found. In the case of paulkerrite it is the second occurrence in the world and in the case. Of earlhannonite it is the third one. Both minerals were formed by alteration of zwieselite. Paulkerrite forms tabular crystals 0.1-0.3 mm in size, beige-white in colour, associated with rockbridgeite I, rockbridgeite II, jahnsite, garnet, pyrite, beraunite, laueite. It is orthorhombic, space group Pbca, a = 10.490 (26), b = 20.685 (101), c = 12.505 (28) Å, V = 2713.42 (13.48) Å3. Earlshannonite forms fine grained aggregates composed of yellow needle-like crystals, 0.1 mm in length, associated with laueite and beraunite. It is monoclinic, space group P21/c, a = 9.914 (12), b = 9.669 (10), c = 5.468 (6) A, (ß = 93.43 (8)°, V = 523.24 (65) Å3.
Josef Staněk, Department of Mineralogy and Petrography, Faculty of Science, J. E. Purkyně University, Kotlářská 2, 61137 Brno, Czechoslovakia