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|System:||Trigonal||Colour:||Pale brownish yellow|
|Name:||Named in 1991 by Teruhiko Sameshima and Yosuke Kawachi in honor of Douglas S. Coombs, professor of geology at the University of Otago, New Zealand. Coombs first described progressive mineralogical changes, especially relating to zeolites, due to low grade burial metamorphism. Coombs named wairakite, ferroceladonite, and ferroaluminoceladonite.|
Mn-analogue of zussmanite.
Classification of Coombsite
|Strunz 8th edition ID:||8/H.40-20|
|Nickel-Strunz 10th (pending) edition ID:||9.EG.35|
9 : SILICATES (Germanates)
E : Phyllosilicates
G : Double nets with 6-membered and larger rings
|Hey's CIM Ref.:||16.16.18|
16 : Silicates Containing Aluminum and other Metals
16 : Aluminosilicates of Mn
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Type Occurrence of Coombsite
|Type Locality:||Watsons Beach, Otago, South Island, New Zealand|
|General Appearance of Type Material:||Aggregates of fibro-lamellar crystals up|
to 20 micron in length, and often shows semispherulitic texture.
|Year of Discovery:||1991|
|Geological Setting of type material:||A 50 cm thick rhodonite-quartz lens.|
|Associated Minerals at type locality:|
Physical Properties of Coombsite
|Colour:||Pale brownish yellow|
Crystallography of Coombsite
|Cell Parameters:||a = 11.82Å, c = 29.14Å|
|Ratio:||a:c = 1 : 2.465|
|Unit Cell Volume:||V 3,525.78 Å³ (Calculated from Unit Cell)|
Optical Data of Coombsite
|RI values:||nω = 1.619 nε = 1.600|
|Maximum Birefringence:||δ = 0.019|
Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Chemical Properties of Coombsite
|Simplified for copy/paste:||K(Mn,Fe,Mg)13(Si,Al)18O42(OH)14|
|Essential elements:||H, K, Mn, O, Si|
|All elements listed in formula:||Al, Fe, H, K, Mg, Mn, O, Si|
Relationship of Coombsite to other Species
|Related Minerals - Nickel-Strunz Grouping):|
|Related Minerals - Hey's Index Grouping:|
Other Names for Coombsite
|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 Coombsite
New Minerals (1997), New Minerals 1990-1994.
Sameshima, T. and Kawachi, Y. (1991): Coombsite, manganese analogue of zussmanite, and associated Mn-silicates, parsettensite and caryopilite, from southeast Otago, New Zealand Journal of Geology and Geophysics: 34, 329-335.
Internet Links for Coombsite
Localities for Coombsite
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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Locality Updated: Bixbyite locality, Sierra Co., New Mexico, USAFrom Steve Stuart, 24th Nov 2014 02:59:37