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|Name:||Originally named in 1868 by James Dwight Dana for a ferrian mica, but redefined as a ferroan mica by Alexander N. Winchell in 1925. Both authors named a mineral after the same locality at Rockport, Cape Ann, Essex Co., Massachusetts, USA.|
Classification of Annite
|Strunz 8th edition ID:||8/H.11-110|
|Nickel-Strunz 10th (pending) edition ID:||9.EC.20|
9 : SILICATES (Germanates)
E : Phyllosilicates
C : Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets
|Dana 8th edition ID:||71.2.2b.3|
71 : PHYLLOSILICATES Sheets of Six-Membered Rings
2 : Sheets of 6-membered rings with 2:1 layers
|Hey's CIM Ref.:||16.18.4|
16 : Silicates Containing Aluminum and other Metals
18 : Aluminosilicates of Fe and alkalis
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Type Occurrence of Annite
|Type Locality:||Rockport, Essex Co., Massachusetts, USA|
|Year of Discovery:||1868|
Physical Properties of Annite
Crystallography of Annite
|Cell Parameters:||a = 5.39Å, b = 9.33Å, c = 10.29Å|
β = 100°
|Ratio:||a:b:c = 0.578 : 1 : 1.103|
|Unit Cell Volume:||V 509.61 Å³ (Calculated from Unit Cell)|
Optical Data of Annite
|RI values:||nα = 1.625 - 1.631 nβ = 1.690 nγ = 1.691 - 1.697|
|2V:||Calculated: 12° to 36°|
|Maximum Birefringence:||δ = 0.066|
Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
|Dispersion:||weak to distinct|
Chemical Properties of Annite
|Simplified for copy/paste:||KFe2+3(AlSi3O10)(OH)2|
|Essential elements:||Al, Fe, H, K, O, Si|
|All elements listed in formula:||Al, Fe, H, K, O, Si|
Relationship of Annite to other Species
|Series:||Forms a series with Phlogopite (see here)|
|Member of:||Mica Group|
|Other Members of Group:|
|Related Minerals - Nickel-Strunz Grouping):|
|Related Minerals - Hey's Index Grouping:|
Other Names for Annite
|Health Warning:||No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.|
References for Annite
Canadian Mineralogist: 36: 905-912.
Hazen, R.M., & C.W. Burnham (1973), The crystal structure of one-layer phlogopite and annite: American Mineralogist: 58: 889-900.
Internet Links for Annite
|Specimens:||The following Annite specimens are currently listed for sale on minfind.com.|
Localities for Annite
The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.