Creedite, Ca3Al2F8(OH)2(SO4) · 2H2O, occurs at the Funtana Raminosa mine, near the village of Gadoni, Sardinia, Italy, associated with Kaolinite and fluorite and, mainly, with carbonate-cyanotrichite, woodwardite and other copper sulfates and carbonates. A microprobe analysis gives the empirical formula Ca3.01Al2.03F7.92(OH)2(S 0.99O4)·2H2O. The strongest lines in the X-ray powder pattern are [d(I/Io)(hkl)]: 6.90(67)(200), 3.94(28)(021), 3.89(24)(202), 3.47(100)(400), 2.602(20)(511), 2.158(18)(133). The mineral is monoclinic, C2/c, with a = 13.936(2), b = 8.600(2), c = 9.982(2)Å, β = 94.38(2)°, V = 11928(3)Å3. The Sardinian creedite represents the first European occurrence.
Creedite from Sardinia, Italy: the first European occurrence
FRAU, FRANCO;
1998-01-01
Abstract
Creedite, Ca3Al2F8(OH)2(SO4) · 2H2O, occurs at the Funtana Raminosa mine, near the village of Gadoni, Sardinia, Italy, associated with Kaolinite and fluorite and, mainly, with carbonate-cyanotrichite, woodwardite and other copper sulfates and carbonates. A microprobe analysis gives the empirical formula Ca3.01Al2.03F7.92(OH)2(S 0.99O4)·2H2O. The strongest lines in the X-ray powder pattern are [d(I/Io)(hkl)]: 6.90(67)(200), 3.94(28)(021), 3.89(24)(202), 3.47(100)(400), 2.602(20)(511), 2.158(18)(133). The mineral is monoclinic, C2/c, with a = 13.936(2), b = 8.600(2), c = 9.982(2)Å, β = 94.38(2)°, V = 11928(3)Å3. The Sardinian creedite represents the first European occurrence.
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