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|Name:||For the Macaulay Institute of Soil Research, Aberdeen, Scotland, UK.|
A swelling iron phyllo-silicate mineral, thought to be composed of layers consisting of twelve iron-oxygen octahedral sheets (equivalent to two hematite unit cells) flanked by two tetrahedral silicate sheets, one on the top and one at the bottom.
Recent research (2009) at NASA has speculated that this mineral may be a significant indicator for the historical presence and distribution of water on Mars.
Classification of Macaulayite
|Strunz 8th edition ID:||8/H.09-30|
|Nickel-Strunz 10th (pending) edition ID:||9.EC.65|
9 : SILICATES (Germanates)
E : Phyllosilicates
C : Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets
|Dana 8th edition ID:||220.127.116.11|
71 : PHYLLOSILICATES Sheets of Six-Membered Rings
2 : Sheets of 6-membered rings with 2:1 layers
|Hey's CIM Ref.:||16.17.2|
16 : Silicates Containing Aluminum and other Metals
17 : Aluminosilicates of Fe
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Type Occurrence of Macaulayite
|Type Locality:||Bennachie, Inverurie, Buchan Grampian (Aberdeenshire), Scotland, UK|
|Geological Setting of type material:||Formed in the breakdown and weathering of granites in tropical conditions.|
Physical Properties of Macaulayite
Crystallography of Macaulayite
|Cell Parameters:||a = 5.03Å, b = 8.72Å, c = 36.34Å|
β = 92°
|Ratio:||a:b:c = 0.577 : 1 : 4.167|
|Unit Cell Volume:||V 1,592.96 Å³ (Calculated from Unit Cell)|
Optical Data of Macaulayite
|RI values:||nα = 1.734|
|Maximum Birefringence:||δ = 1.734|
Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
|Dispersion:||r > v|
Chemical Properties of Macaulayite
|Essential elements:||Fe, H, O, Si|
|All elements listed in formula:||Al, Fe, H, O, Si|
Relationship of Macaulayite to other Species
|Related Minerals - Nickel-Strunz Grouping):|
|Related Minerals - Hey's Index Grouping:|
Other Names for Macaulayite
|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 Macaulayite
Wilson, M.J., J.D. Russell, J.M. Tait, D.R. Clark, and A.R. Fraser (1984): Macaulayite, a new mineral from north-east Scotland. Mineral. Mag., 48, 127-129.
American Mineralogist (1985): 70: 1330.
Sawcer, D.E., Goodman, B.A., Russell, J.D., and Thomas, M.F. (1988): A Mössbauer Effect Study of the Mineral Macaulayite. Physics and Chemistry of Minerals 16(1), 73-77.
NASA tests Aberdeenshire find for life on Mars clues - BBC News Website(2009): http://news.bbc.co.uk/1/hi/scotland/north_east/8400025.stm
Internet Links for Macaulayite
Localities for Macaulayite
(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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