Talmessite Mineral Data

General Talmessite Information
Chemical Formula:	Ca2Mg(AsO4)2•2(H2O)
Composition:	Molecular Weight = 418.33 gm
	Calcium 19.16 % Ca 26.81 % CaO
	Magnesium 5.81 % Mg 9.63 % MgO
	Arsenic 35.82 % As 54.94 % As₂O₅
	Hydrogen 0.96 % H 8.61 % H₂O
	Oxygen 38.25 % O
	______ ______
	100.00 % 100.00 % = TOTAL OXIDE
Empirical Formula:	Ca₂Mg(AsO₄)₂•2(H₂O)
Environment:	Secondary species formed typically in the oxidized zone of some hydrothermal mineral deposits, an alteration product of realgar, orpiment, or Cu-Ni arsenides.
IMA Status:	Approved IMA 1960
Locality:	Talmessi mine, 35 km west of Anarak, Iran. In the Arhbar (Aghbar) and A�it Ahmane mines, Bou Azzer district, Morocco. Link to MinDat.org Location Data.
Name Origin:	Named for the locality.
Name Pronunciation:	Talmessite + Pronunciation
Synonym:	ICSD 200008
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