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Single crystals of ␥-Cu 2 V 2 O 7 were obtained by the method of chemical transport reactions. The crystal structure [triclinic, P1, a 5.0873(10), b 5.8233(11), c 9.4020(18) Å, ␣ 99.780(3), ␤ 97.253(3), ␥ 97.202(3)°, V 269.20(9) Å 3 , Z = 2] has been solved by direct methods and refined to R 1 = 0.021 (wR 2 = 0.049) using 949 unique observed reflections with |F o | ≥ 4 F . The atomic arrangement contains two symmetrically independent Cu 2+ cations. The Cu(1) site is coordinated by six O atoms to form a distorted Cu(1)O 6 octahedron, whereas the Cu (2) site is coordinated by five O atoms arranged at the vertices of an elongate Cu(2)O 5 square pyramid. Two symmetrically independent V 5+ cations are tetrahedrally coordinated by four O atoms each. The O(5) atom bridges the V(1)O 4 and V(2)O 4 tetrahedra. The Cu(1)O 6 octahedra and Cu(2)O 5 square pyramids form two types of chains running parallel to the a axis. The chains are linked by V 2 O 7 groups into a complex heteropolyhedral framework. The structure of ␥-Cu 2 V 2 O 7 is closely related to the structures of ␣-Cu 2 V 2 O 7 (blossite) and ␤-Cu 2 V 2 O 7 (ziesite). The three structures are based upon chains of edge-sharing Cu 2+ polyhedra linked by V 2 O 7 groups. Similarity of the structure of ␥-Cu 2 V 2 O 7 to the structures of blossite and ziesite indicates possible formation of this phase under natural conditions, such as those that occur in "dry" high-temperature fumaroles of the Izalco (El Salvador) and Tolbachik (Kamchatka, Russia) volcanoes. The structure of ␥-Cu 2 V 2 O 7 can also be considered as a triclinically distorted derivative of the ␤-A 2 P 2 O 7 structure-type.

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eginning with the 2003 Tucson gem shows, cesium-rich "beryl" from Ambatovita, Madagascar, created excitement among gem collectors and connoisseurs due to its deep purplish pink color (figure 1) and the attractive chatoyancy displayed by some of the material. Although it was sold during and after the Tucson gem shows as "raspberyl," "red beryl," "pink beryl," "hot pinkred beryl," and especially "raspberry beryl," subsequent examinations (see, e.g., Simmons et al., 2003) revealed properties that were anomalous for beryl and were associated with very high concentrations of cesium (Cs). In September 2003, the International Mineralogical Association approved the name pezzottaite (pe-zó-ta-ite) for this new species of the beryl group. It is named after Dr. Federico Pezzotta (Natural History Museum, Milan, Italy), who was among the first to investigate this new mineral, in recognition of his scientific contributions to the mineralogy of Madagascar (Hawthorne et al., 2003). With the addition of pezzottaite-ideally Cs(Be 2 Li)Al 2 Si 6 O 18-the beryl group consists of four members. The other three (all hexagonal) are: beryl (Be 3 Al 2 Si 6 O 18 ; Aurisicchio et al., 1988), bazzite (Be 3 Sc 2 Si 6 O 18 ; Armbruster et al., 1995), and stoppaniite (Be 3 Fe 2 Si 6 O 18 ; Ferraris et al., 1998; Della Ventura et al., 2000). Pezzottaite, which is rhombohedral, is not a Cs-rich beryl but rather a new mineral species that is closely related to beryl. Another mineral, indialite ([Al 2 Si]Mg 2 [Al 2 Si 4 ]O 18 ; Meagher and Gibbs, 1977), is also sometimes included in the beryl group. Of these, only beryl and pezzottaite have been found in gem quality. (Note: In this article, "beryl" refers to the mineral species, rather than the group, unless otherwise specified.) Pezzottaite has been confirmed from just one deposit in Madagascar, the Sakavalana granitic pegmatite located near Ambatovita in a remote area of the central highlands. In addition to material from this locality, a sample of Cs-rich "morganite" from Afghanistan described by Hänni and Krzemnicki (2003) has now been recognized as pezzottaite (H. Hänni, pers. comm., 2003). Observations of the crystal morphology of pezzottaite from Madagascar 284

Ansermetite, MnV 2 O 6 •4H 2 O, is a new mineral species from the metamorphosed synsedimentary exhalative Mn deposit of Fianel, Val Ferrera, Eastern Swiss Alps. The crystals are carmine red, transparent, with an orange streak and adamantine luster. The Mohs hardness is ~3, D calc = 2.49 g/cm 3 , D meas = 2.57(2) g/cm 3. Ansermetite has an excellent cleavage along {110}, the prism, and an uneven fracture. It is biaxial with n min = 1.797 and n max = 1.856 (Na D , 22.5°C), strongly pleochroic between yellow orange (X) and ruby red (Z), and non-fluorescent. Chemically, ansermetite is near the end-member composition MnV 2 O 6 •4H 2 O, containing only small amounts of arsenic (0.93 wt% As 2 O 5) and strontium (0.20 wt% SrO). Ansermetite is monoclinic, C2/c, a 13.171(2), b 10.128(1), c 6.983(1) Å, ␤ 111.572(2)°, V 866.3(2) Å 3 , Z = 4. The crystal structure was solved with direct methods on the basis of 701 reflections with I > 2(I) and refined to R 1 = 7.01%. The structure is isotypic with that of synthetic CoV 2 O 6 •4H 2 O and MnV 2 O 6 •4H 2 O. It contains V 5+ in distorted square pyramidal coordination with five atoms of oxygen, and Mn 2+ in octahedral coordination with four atoms of oxygen and two H 2 O groups. The VO 5 polyhedra share edges to form chains extending along [001], and linked by MnO 4 (H 2 O) 2 octahedra. This arrangement results in a three-dimensional framework defining tunnels that host the two H 2 O groups per formula unit belonging to MnO 4 (H 2 O) 2 octahedra as well and two additional free H 2 O groups. Ansermetite forms crystalline crusts up to ~500 m in thickness and several square centimeters in surface filling thin open fractures cross-cutting V-rich Mn-Fe silicate-oxide ores. Ansermetite is associated to fianelite, Mn 2 V(V,As)O 7 •2H 2 O, Fe oxyhydroxides and silica. Ansermetite and fianelite represent the latest stage of V mobility at the Fianel deposit. Ansermetite is stable at ambient conditions, but is unstable in air and aqueous solutions at temperatures above ~50 to 85°C. Ansermetite is likely to have crystallized from near neutral to mildly acidic groundwater during the Quaternary.