CNMMN Check-list 2005 page 1 CHECK-LIST FOR NEW-MINERAL PROPOSALS (2005) NOTE: Wherever numerical data are to be entered, the spaces are followed by brackets. Please give estimated errors or estimated standard deviations in the brackets. For example, a 12.345(9). GENERAL INFORMATION MINERAL NAME: Rruffite 2+ CHEMICAL FORMULA: Ca2Cu (AsO4)2·2H2O CRYSTAL SYSTEM: Monoclinic SPACE GROUP: P21/c (#14) POINT GROUP: (if space group is unknown) a=5.8618(2) Å b=12.7854(5) Å c=5.7025(2) Å α=90º β=109.425(2)º γ=90º V=403.05(3) Å3 Z = 2 AUTHORS' NAMES AND COMPLETE ADDRESS (also e-mail for the corresponding author): Hexiong Yang, Robert A. Jenkins, Robert T. Downs, Stanley H. Evans Department of Geosciences 1040 E. 4th Street Tucson, AZ 85721-0077, USA Email address of the corresponding author: [email protected] OCCURRENCE: Give specific details on the geographic locality. In cases of remote localities, please give latitude and longitude. Maria Catalina mine, Pampa Larga Mining District, Tierra Amarilla, Chile (latitude 22°3' S. and longitude 68°30' W.) (Parker et al. 1963). ASSOCIATED MINERALS: Give the complete list. (see Fig. 1 in the supplemental file) Conichalcite CaCuAsO4(OH) (An untwined crystal was studied from this sample, see Henderson et al. 2008). Mansfieldite AlAsO4·2H2O Barite BaSO4 Alumopharmacosiderite KAl4(AsO4)3(OH)4·6.5H2O Philipsbornite PbAl3(AsO4)(AsO3OH)(OH)6 Lavendulan NaCaCu5(AsO4)4Cl·5H2O 3+ Barahonaite-(Al) (Ca,Cu,Na,Fe ,Al)12Al2(AsO4)8(OH,Cl)x·nH2O ORIGIN OF THE MINERAL: Give any information on how the mineral was formed. CNMMN Check-list 2005 page 2 Similar to other associated minerals (conichalcite, mansfieldite, and metazeunerite), rruffite is considered as a secondary mineral as well and it forms in the oxidation zone of a Cu-As ore body. APPEARANCE AND PHYSICAL PROPERTIES GENERAL APPEARANCE: Give a short description including the kind of crystals or grains, the kind of aggregates, the size of individual grains or crystals (in metric units) and the size of aggregates. Crystals are commonly in granular or blocky aggregates and druses (up to 0.05 x 0.05 x 0.05 mm). Twinning is common on (100). PHYSICAL PROPERTIES COLOUR (megascopic): Pale- or light-blue in transmitted light STREAK: pale-blue to white (colour of the powder) LUSTRE: vitreous: X adamantine ....... metallic ....... other ..................................................... (specify) OPAQUE ........ TRANSLUCENT ........ TRANSPARENT: X FLUORESCENCE: none.................................................................................................. (give colours and wavelengths of excitation) HARDNESS: Mohs: ~3.0 Micro-indentation: VHN load ......... g mean .......…. range ........................….. kg/mm2 CLEAVAGE: . {010} perfect....................................................................................... (directions and perfection) PARTING: : None....................................................................................... (directions and perfection) TENACITY: brittle: X sectile ..... malleable ..... other ........................................................... FRACTURE: uneven DENSITY (meas.): 3.79( 3 ) g/cm3 DENSITY (calc.): 3.77 ( 2 ) g/cm3 Method used to measure density: heavy-liquid hydrous solution. OTHER DATA: (Use additional pages, if necessary) THERMAL: INFRA RED: OTHER: Raman spectra (see Fig. 2 and Table 1 in the supplemental data file). CNMMN Check-list 2005 page 3 OPTICAL PROPERTIES NONMETALLIC MINERALS: (Give estimated errors) WAVELENGTH = ............. nm ISOTROPIC: n .................... ( ) UNIAXIAL (+) (−): ω .................... ( ) ε .................... ( ) BIAXIAL (−) : α 1.725 (1) β 1.734 ( 1 ) γ 1.740 ( 1 ) 2V (meas.): -80(2)º 2V (calc.): -78º DISPERSION: … r < v …; weak ORIENTATION: (As complete as possible): Y = b, X ∧ c = 49º PLEOCHROISM: none METALLIC MINERALS COLOUR (microscopic): ............................................................................................ BIREFLECTANCE: .................................................................................................. PLEOCHROISM: ..................................................................................................... ANISOTROPY: ....................................................................................................... INTERNAL REFLECTIONS: ...................................................................................... REFLECTANCE VALUES (Measurements at the four wavelengths marked COM, below, are the minimum requirements): Standard: .................... (It should be one of those recommended by the Commission on Ore Mineralogy, I.M.A.). Measured in air? yes ..... no ..... Measured in oil? yes ..... no ..... (refractive index of oil: ..................) For multiple R values, please indicate: Rmax./Rmin., RO/RE, etc. ................................... 400nm .................................. 560nm ................................... 420nm .................................. 580nm ................................... 440nm .................................. 589nm (COM) ................................... 460nm .................................. 600nm ................................... 470nm (COM) .................................. 620nm ................................... 480nm .................................. 640nm ................................... 500nm .................................. 650nm (COM) ................................... 520nm .................................. 660nm ................................... 540nm .................................. 680nm ................................... 546nm (COM) .................................. 700nm OTHER OPTICAL DATA CNMMN Check-list 2005 page 4 CHEMICAL DATA TYPE OF ANALYSIS: WET ….. ELECTRON MICROPROBE: X OTHER: ................................................ ELECTRON MICROPROBE: WDS/EDS; kV: 10; nA: 5; beam diameter: 20 μm H2O ANALYTICAL METHOD: by the combination of electron microprobe and X-ray structure data. The presence of water was also confirmed by the Raman spectroscopic measurements (see Fig. 2a in the supplemental file). CO2 ANALYTICAL METHOD ......................................................................... NOTE: If H2O or CO2 was not determined directly, give the reason(s). We did not have the access to other techniques. Furthermore, we have very few crystals available. However, we believe that the results from the combination of electron microprobe analysis and X-ray structure refinement can be justified. ANALYTICAL RESULTS: Number of analyses: 9 For multiple analyses please give ranges and standard deviations of the data. Please give below the analytical data that conform to the material from which the physical, optical and crystal data were obtained. Constituent Wt.% Range Stand. Dev. Probe Standard As2O5 50.37 49.63-50.83 0.39 As metal CaO 24.55 24.18-24.81 0.23 diopside CuO 17.47 17.16-17.80 0.23 chalcopyrite SO3 0.11 0.04-0.16 0.04 chalcopyrite Total 92.50 92.06-93.26 0.62 (Trace amounts of Fe and Mg were also observed by WDS, but are under detection limits). CNMMN Check-list 2005 page 5 EMPIRICAL FORMULA: Ca2.01Cu1.01(AsO4)2.02•1.9H2O (GIVE BASIS OF CALCULATION, SUCH AS NUMBER OF ANIONS, ETC.): The number of oxygen atoms bonded to As5+, which is 4. SIMPLIFIED FORMULA: Ca2Cu(AsO4)2•2H2O CHEMICAL TESTS (etching, solution): CRYSTALLOGRAPHY SINGLE-CRYSTAL STUDY: METHOD: Precession ....... Weissenberg ....... 4-circle: X. Other ............................ NOTE: If no single-crystal study was done, explain why. CRYSTAL SYSTEM: Monoclinic SPACE GROUP: P21/c (#14) POINT GROUP (if space group is unknown): .......... CELL PARAMETERS: a= 5.8618 (2) Å α =90º b= 12.7854 (5) Å β =109.425(2)º c= 5.7025(2) Å γ = 90º V =403.05(3) Å3 Z = 2 POWDER DATA: (For CuKα: X, FeKα …… ) Debye-Scherrer ...... Gandolfi ...... Diffractometer: Bruker APEX2 (MoKα ) Guinier ...... Diameter of camera .........… mm CELL PARAMETERS REFINED FROM POWDER DATA? YES: X NO ..... CRYSTAL SYSTEM: Monoclinic SPACE GROUP: ..............….. POINT GROUP (if space group is unknown): ............... a= 5.892 (5) Å α =90º b= 12.724 (8) Å β =109.28(9)º c= 5.722(4) Å γ = 90º V =404.9(4) Å3 Z = 2 ON A SEPARATE PAGE PLEASE SUPPLY THE COMPLETE X-RAY POWDER DIFFRACTION DATA AS SHOWN BELOW. GIVE IN BOLD THE INTENSITIES OF THE STRONGEST LINES. I dmeas. dcalc. hkl CNMMN Check-list 2005 page 6 (see Figure 3 and Table 2 in the supplemental data file) CRYSTAL STRUCTURE: (Summarize the details) R1 = 0.023, wR=0.060 (see Table 3 in the supplemental data file) The structure of rruffite is isostructural with roselite (Hawthorne and Ferguson 1977) and characterized by isolated CuO4(OH2)2 octahedra that are linked by corner-sharing with AsO4 tetrahedra to form chains extending parallel to the c-axis (Fig. 4). These chains are linked together by 2- the large Ca cations and hydrogen bonding. The Ca cations are 7-coordinated (6 O + 1 H2O). The CuO4(OH2)2 octahedra are noticeably elongated, due to the strong Jahn-Teller effect, similar to that 2+ found in krhnkite Na2Cu (SO4)2•2H2O (Hawthorne and Ferguson 1975). MORPHOLOGY: HABIT: commonly in granular or blocky aggregates and druses. FORMS: dominated by {100}, {110}, {120}, {010} TWINNING: on {010}, perfect OTHER DATA: a:b:c: 0.458:1.000:0.446 (from unit-cell parameters) MISCELLANEOUS DATA NAME: If named for a living person, indicate his or her acceptance and year of birth. If named for a deceased person, please give years of birth and death. For names transliterated from the Cyrillic alphabet, please give the original