Tondiite, with the simplified formula Cu3Mg(OH)6Cl2, occurs as a rare supergene mineral in a phonolitic tephrite from the type locality, Vesuvius volcano, Italy, as well as associated with haydeeite in the Santo Domingo Mine, Arica Province, Chile. It is emerald green to bright green in colour and occurs in irregularly shaped crystals, often with stepped faces. Its calculated density is 3.503 g cm3. Tondiite crystallizes with the herbertsmithite structure type, space group R3¯ m. Lattice parameters are a = 6.8377(7) A ˚ and c = 14.088(2)A˚ for the holotype material. The c parameter may vary with Mg/Cu ratio and the presence of impurity atoms. The five strongest lines in the calculated powder diffraction pattern are [d in A ˚ (I)(hkil)]: 5.459(88)(101¯1), 3.419(22)(112¯ 0), 2.764(100)(112¯ 3), 2.266(54)(022¯4), 1.706(26)(224¯ 0). Several tondiite crystals have been examined by single-crystal X-ray diffraction and by electron microprobe analysis. The observed Mg content ranges between 0.6 and 0.7 atoms per formula unit. The structural role of Mg is discussed.
Tondiite, Cu3Mg(OH)6Cl2, the Mg-analog of herbertsmithite / Malcherek, T; Bindi, L; Dini, M; Ghiara, MARIA ROSARIA; MOLINA DONOSO, A; Nestola, F; Rossi, Manuela; Schluter, J.. - In: MINERALOGICAL MAGAZINE. - ISSN 0026-461X. - 78:3(2014), pp. 583-590. [10.1180/minmag.2014.078.3.08]
Tondiite, Cu3Mg(OH)6Cl2, the Mg-analog of herbertsmithite
GHIARA, MARIA ROSARIA;ROSSI, MANUELA;
2014
Abstract
Tondiite, with the simplified formula Cu3Mg(OH)6Cl2, occurs as a rare supergene mineral in a phonolitic tephrite from the type locality, Vesuvius volcano, Italy, as well as associated with haydeeite in the Santo Domingo Mine, Arica Province, Chile. It is emerald green to bright green in colour and occurs in irregularly shaped crystals, often with stepped faces. Its calculated density is 3.503 g cm3. Tondiite crystallizes with the herbertsmithite structure type, space group R3¯ m. Lattice parameters are a = 6.8377(7) A ˚ and c = 14.088(2)A˚ for the holotype material. The c parameter may vary with Mg/Cu ratio and the presence of impurity atoms. The five strongest lines in the calculated powder diffraction pattern are [d in A ˚ (I)(hkil)]: 5.459(88)(101¯1), 3.419(22)(112¯ 0), 2.764(100)(112¯ 3), 2.266(54)(022¯4), 1.706(26)(224¯ 0). Several tondiite crystals have been examined by single-crystal X-ray diffraction and by electron microprobe analysis. The observed Mg content ranges between 0.6 and 0.7 atoms per formula unit. The structural role of Mg is discussed.File | Dimensione | Formato | |
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2014. tondiite the Mg-analogue of Mineralogical Magazine, June 2014, Vol. 78(3), pp. 583–590.pdf
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