Articles | Volume 32, issue 3
Research article
17 Jun 2020
Research article |  | 17 Jun 2020

Laurentthomasite, Mg2K(Be2Al)Si12O30: a new milarite-group-type member from the Ihorombe region, Fianarantsoa Province, Madagascar

Cristiano Ferraris, Isabella Pignatelli, Fernando Cámara, Giancarlo Parodi, Sylvain Pont, Martin Schreyer, and Fengxia Wei

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Cited articles

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Armbruster, T.: Si, Al ordering in the double-ring silicate armenite, BaCa2Al6Si9O30 • 2H2O: A single-crystal X-ray and 29Si MAS NMR study, Am. Mineral., 84, 92–101, 1999. 
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Cempírek, J., Grew, E. S., Kampf, A. R., Ma, C., Novák, M., Gadas, P., Škoda, R., Vašinová-Galiová, M., Pezzotta, F., Groat, L. A., and Krivovichev, S.: Vránaite, ideally Al16B4Si4O38, a new mineral related to boralsilite, Al16B6Si2O37, from the Manjaka pegmatite, Sahatany Valley, Madagascar, Am. Mineral., 101, 2108–2117,, 2016. 
Short summary
Laurentthomasite is a new mineral from Madagascar showing a very strong dichroism going from deep blue to yellow-green colours. The physical and chemical characteristics of this gem quality mineral bring it to the attention of the jewel industry as well as collectors of cut stones.