Research output: Contribution to journal › Article › peer-review
Antofagastaite, Na2Ca(SO4)2·1.5H2O, a new mineral related to syngenite. / Pekov, Igor V. ; Kovrugin, Vadim M. Kovrugin; Siidra, Oleg I. ; Chukanov, Nikita V. ; Belakovskiy, Dmitry I. ; Koshlyakova, Natalya N.; Yapaskurt, Vasiliy O. ; Turchkova, Anna G. ; Möhn, Gerhard.
In: Mineralogical Magazine, 12.04.2019.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Antofagastaite, Na2Ca(SO4)2·1.5H2O, a new mineral related to syngenite
AU - Pekov, Igor V.
AU - Kovrugin, Vadim M. Kovrugin
AU - Siidra, Oleg I.
AU - Chukanov, Nikita V.
AU - Belakovskiy, Dmitry I.
AU - Koshlyakova, Natalya N.
AU - Yapaskurt, Vasiliy O.
AU - Turchkova, Anna G.
AU - Möhn, Gerhard
PY - 2019/4/12
Y1 - 2019/4/12
N2 - The new mineral antofagastaite, ideally Na2Ca(SO4)2·1.5H2O, was found in the oxidation zone of sulfide–quartz veins at the abandoned Coronel Manuel Rodríguez mine, Mejillones, Antofagasta Province, Antofagasta Region, Chile. It is associated with sideronatrite, metasideronatrite, aubertite, gypsum, ferrinatrite, glauberite, amarillite and an unidentified Fe phosphate. Antofagastaite occurs as prismatic crystals up to 0.5 mm × 1 mm × 5 mm, elongated along [010], typically combined in open-work aggregates up to 1 cm across. Antofagastaite is transparent and colourless, with vitreous lustre. It is brittle; the Mohs’ hardness is ca 3. Cleavage is distinct on (001). Dmeas. is 2.42(1) and Dcalc. is 2.465 g cm−3. Antofagastaite is optically biaxial (–), α = 1.489(2), β = 1.508(2), γ = 1.510(2) and 2Vmeas. = 40(10)°. The IR spectrum is reported. Chemical composition (wt.%, electron microprobe, H2O determined by gas chromatography) is: Na2O 20.85, CaO 17.42, SO3 52.56, H2O 7.93, total 98.76. The empirical formula (based on 8 O atoms belonging to sulfate anions per formula unit with all H belonging to H2O molecules) is Na2.06Ca0.95S2.01O8·1.35H2O. Antofagastaite is monoclinic, P21/m, a = 6.4596(4), b = 6.8703(5), c = 9.4685(7) Å, β = 104.580(4)°, V = 406.67(5) Å3 and Z = 2. The strongest reflections of the powder XRD pattern [d, Å (I, %) (hkl)] are: 9.17 (100) (001), 5.501 (57) (011), 3.437 (59) (020), 3.058 (43) (003), 2.918 (50) (2¯11), 2.795 (35) (013) and 2.753 (50) (121, 201). The crystal structure was solved based on single-crystal X-ray diffraction data, R1 = 5.71%. The structure of antofagastaite consists of ordered and disordered blocks and is related to syngenite K2Ca(SO4)2·H2O. Incorporation of additional H2O molecules in the syngenite-type structure results in disorder of the one of the two tetrahedral sulfate groups occurring in antofagastaite. In addition to the above-reported type material, antofagastaite together with syngenite and blödite occurs in the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia.
AB - The new mineral antofagastaite, ideally Na2Ca(SO4)2·1.5H2O, was found in the oxidation zone of sulfide–quartz veins at the abandoned Coronel Manuel Rodríguez mine, Mejillones, Antofagasta Province, Antofagasta Region, Chile. It is associated with sideronatrite, metasideronatrite, aubertite, gypsum, ferrinatrite, glauberite, amarillite and an unidentified Fe phosphate. Antofagastaite occurs as prismatic crystals up to 0.5 mm × 1 mm × 5 mm, elongated along [010], typically combined in open-work aggregates up to 1 cm across. Antofagastaite is transparent and colourless, with vitreous lustre. It is brittle; the Mohs’ hardness is ca 3. Cleavage is distinct on (001). Dmeas. is 2.42(1) and Dcalc. is 2.465 g cm−3. Antofagastaite is optically biaxial (–), α = 1.489(2), β = 1.508(2), γ = 1.510(2) and 2Vmeas. = 40(10)°. The IR spectrum is reported. Chemical composition (wt.%, electron microprobe, H2O determined by gas chromatography) is: Na2O 20.85, CaO 17.42, SO3 52.56, H2O 7.93, total 98.76. The empirical formula (based on 8 O atoms belonging to sulfate anions per formula unit with all H belonging to H2O molecules) is Na2.06Ca0.95S2.01O8·1.35H2O. Antofagastaite is monoclinic, P21/m, a = 6.4596(4), b = 6.8703(5), c = 9.4685(7) Å, β = 104.580(4)°, V = 406.67(5) Å3 and Z = 2. The strongest reflections of the powder XRD pattern [d, Å (I, %) (hkl)] are: 9.17 (100) (001), 5.501 (57) (011), 3.437 (59) (020), 3.058 (43) (003), 2.918 (50) (2¯11), 2.795 (35) (013) and 2.753 (50) (121, 201). The crystal structure was solved based on single-crystal X-ray diffraction data, R1 = 5.71%. The structure of antofagastaite consists of ordered and disordered blocks and is related to syngenite K2Ca(SO4)2·H2O. Incorporation of additional H2O molecules in the syngenite-type structure results in disorder of the one of the two tetrahedral sulfate groups occurring in antofagastaite. In addition to the above-reported type material, antofagastaite together with syngenite and blödite occurs in the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia.
KW - antofagastaite
KW - new mineral
KW - hydrated sodium calcium sulfate
KW - syngenite
KW - Crystal structure
KW - oxidation zone of ore deposit
KW - Coronel Manuel Rodríguez mine
KW - Atacama Desert
KW - fumarole
KW - Tolbachik volcano
UR - https://www.researchgate.net/publication/332381647_Antofagastaite_Na2CaSO4215H2O_a_new_mineral_related_to_syngenite
M3 - Article
JO - Mineralogical Magazine
JF - Mineralogical Magazine
SN - 0026-461X
ER -
ID: 47922492