Annite Mineral Data

General Annite Information
Chemical Formula:	KFe++3AlSi3O10(OH,F)2
Composition:	Molecular Weight = 512.88 gm
	Potassium 7.62 % K 9.18 % K₂O
	Aluminum 5.26 % Al 9.94 % Al₂O₃
	Iron 32.67 % Fe 42.03 % FeO
	Silicon 16.43 % Si 35.15 % SiO₂
	Hydrogen 0.29 % H 2.63 % H₂O
	Oxygen 35.87 % O
	Fluorine 1.85 % F 1.85 % F
	- % F -0.78 % -O=F₂
	______ ______
	100.00 % 100.00 % = TOTAL OXIDE
Empirical Formula:	KFe²⁺₃AlSi₃O₁₀(OH)_1.5F_0.5
Environment:	In magnesium-poor igneous and metamorphic rocks.
IMA Status:	Valid Species (Pre-IMA) 1863
Locality:	In the USA, from Cape Ann, east of Rockport, Essex Co., Massachusetts, and on Pikes Peak, El Paso Co., Colorado. From Mont Saint-Hilaire, Quebec, Canada. Link to MinDat.org Location Data.
Name Origin:	For the first noted occurrence at Cape Ann, Massachusetts, USA.
Name Pronunciation:	Annite