TY - JOUR
T1 - Leverettite from the Torrecillas mine, Iquique Provence, Chile : the Co-analogue of herbertsmithite
AU - Kampf, A. R.
AU - Sciberras, M. J.
AU - Williams, P. A.
AU - Dini, M.
AU - Molina Donoso, A. A.
PY - 2013
Y1 - 2013
N2 - The new mineral leverettite (IMA 2013-011), ideally Cu3CoCl 2(OH)6, was found at the Torrecillas mine, Salar Grande, Iquique Province, Chile, where it occurs as a supergene alteration phase in association with akaganéite, anhydrite, chalcophanite, goethite, halite, manganite, pyrite, quartz and todorokite. Crystals of leverettite are steep rhombohedra to 1 mm with {101} prominent and modified by {001}, sometimes forming V-shaped twins by reflection on {102̄}. The crystals can also form finger-like, parallel stacked growths along the c axis. The new mineral is medium to deep green in colour and has a light green streak. Crystals are transparent with a vitreous lustre. Mohs hardness is ~3 and the crystals have a brittle tenacity, a perfect cleavage on {101} and a conchoidal fracture. The measured density is 3.64(2) g cm-3 and calculated density based on the empirical formula is 3.709 g cm-3. Optically, leverettite is uniaxial (-) with o and ε > 1.8 and exhibits pleochroism with O (bluish green) > E (slightly yellowish green). The empirical formula, determined from electron-microprobe analyses is Cu3(Co0.43Cu 0.40Mn0.17Ni0.07Mg0.01) Σ1.08Cl1.87O6.13H6. Leverettite is trigonal (hexagonal), space group R3̄m, unit-cell parameters a = 6.8436(6) and c = 14.064(1) Ã
, V = 570.42(8) Ã
3, Z = 3. The eight strongest X-ray powder diffraction lines are [dobs Ã
(I)(hkl)]: 5.469(90)(101), 4.701(18)(003), 2.905(22)(021), 2.766(100)(113), 2.269(66)(024), 1.822(26)(033), 1.711(33)(220), 1.383(23)(128). The structure, refined to R1 = 0.023 for 183 Fo > 4sF reflections, shows leverettite to be isostructural with herbertsmithite and gillardite.
AB - The new mineral leverettite (IMA 2013-011), ideally Cu3CoCl 2(OH)6, was found at the Torrecillas mine, Salar Grande, Iquique Province, Chile, where it occurs as a supergene alteration phase in association with akaganéite, anhydrite, chalcophanite, goethite, halite, manganite, pyrite, quartz and todorokite. Crystals of leverettite are steep rhombohedra to 1 mm with {101} prominent and modified by {001}, sometimes forming V-shaped twins by reflection on {102̄}. The crystals can also form finger-like, parallel stacked growths along the c axis. The new mineral is medium to deep green in colour and has a light green streak. Crystals are transparent with a vitreous lustre. Mohs hardness is ~3 and the crystals have a brittle tenacity, a perfect cleavage on {101} and a conchoidal fracture. The measured density is 3.64(2) g cm-3 and calculated density based on the empirical formula is 3.709 g cm-3. Optically, leverettite is uniaxial (-) with o and ε > 1.8 and exhibits pleochroism with O (bluish green) > E (slightly yellowish green). The empirical formula, determined from electron-microprobe analyses is Cu3(Co0.43Cu 0.40Mn0.17Ni0.07Mg0.01) Σ1.08Cl1.87O6.13H6. Leverettite is trigonal (hexagonal), space group R3̄m, unit-cell parameters a = 6.8436(6) and c = 14.064(1) Ã
, V = 570.42(8) Ã
3, Z = 3. The eight strongest X-ray powder diffraction lines are [dobs Ã
(I)(hkl)]: 5.469(90)(101), 4.701(18)(003), 2.905(22)(021), 2.766(100)(113), 2.269(66)(024), 1.822(26)(033), 1.711(33)(220), 1.383(23)(128). The structure, refined to R1 = 0.023 for 183 Fo > 4sF reflections, shows leverettite to be isostructural with herbertsmithite and gillardite.
UR - http://handle.uws.edu.au:8081/1959.7/538323
U2 - 10.1180/minmag.2013.077.7.14
DO - 10.1180/minmag.2013.077.7.14
M3 - Article
SN - 0026-461X
VL - 77
SP - 3047
EP - 3054
JO - Mineralogical Magazine
JF - Mineralogical Magazine
IS - 7
ER -