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|Lustre:||Vitreous||Hardness:||3 - 4|
|Name:||The mineral was named after Dr. Richard A. Eggleton of the Australian National University.|
Ganophyllite Group. The sodium analogue of Ganophyllite.
Not to be confused with the unrelated mercury mineral Eglestonite.
Classification of Eggletonite
|Strunz 8th edition ID:||8/H.17-70|
|Nickel-Strunz 10th (pending) edition ID:||9.EG.30|
9 : SILICATES (Germanates)
E : Phyllosilicates
G : Double nets with 6-membered and larger rings
|Dana 7th edition ID:||184.108.40.206|
|Dana 8th edition ID:||220.127.116.11|
74 : PHYLLOSILICATES Modulated Layers
1 : Modulated Layers with joined islands
|Hey's CIM Ref.:||16.16.14|
16 : Silicates Containing Aluminum and other Metals
16 : Aluminosilicates of Mn
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Type Occurrence of Eggletonite
|Type Locality:||Big Rock Quarry (3M Quarry; Arch Street Pike Quarry), Granite Mountain area, Little Rock, Pulaski Co., Arkansas, USA|
|Year of Discovery:||1984|
Physical Properties of Eggletonite
|Hardness (Mohs):||3 - 4|
Crystallography of Eggletonite
|Cell Parameters:||a = 5.55Å, b = 13.72Å, c = 25Å|
β = 93.95°
|Ratio:||a:b:c = 0.405 : 1 : 1.822|
|Unit Cell Volume:||V 1,899.13 Å³ (Calculated from Unit Cell)|
Optical Data of Eggletonite
|RI values:||nα = 1.566 nβ = 1.606 nγ = 1.606|
|Maximum Birefringence:||δ = 0.040|
Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
|Dispersion:||r > v strong|
Chemical Properties of Eggletonite
|Essential elements:||H, Mn, Na, O, Si|
|All elements listed in formula:||Al, Ca, Fe, H, K, Mn, Na, O, Si|
Relationship of Eggletonite to other Species
|Member of:||Ganophyllite Group|
|Other Members of Group:|
|Related Minerals - Nickel-Strunz Grouping):|
|Related Minerals - Hey's Index Grouping:|
Other Names for Eggletonite
|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 Eggletonite
Peacor, D. R.; Dunn, P. J. and Simmons, W. B. (1984): Eggletonite, the sodium analog of ganophyllite.: Mineralogical Magazine: 48, 93-96.
American Mineralogist: 70: 436.
Internet Links for Eggletonite
Localities for Eggletonite
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.
(TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
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