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|Name:||Named after George Atwater Rankin, physical chemist at the Geophysical Laboratory.|
This page provides mineralogical data about Rankinite.
Classification of Rankinite
|IMA status:||Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"|
|Strunz 8th edition ID:||8/C.03-10|
|Nickel-Strunz 10th (pending) edition ID:||9.BC.15|
9 : SILICATES (Germanates)
B : Sorosilicates
C : Si2O7 groups, without non-tetrahedral anions; cations in octahedral  and greater coordination
|Dana 8th edition ID:||188.8.131.52|
55 : SOROSILICATES Si2O7 Groups,Generally with no Additional Anions
3 : Si2O7 Groups, Generally with no Additional Anions with cations in  coordination
|Hey's CIM Ref.:||14.5.4|
14 : Silicates not Containing Aluminum
5 : Silicates of Ca
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Type Occurrence of Rankinite
|Type Locality:||Scawt Hill, Larne, Co. Antrim, Northern Ireland, UK|
|Year of Discovery:||1942|
Physical Properties of Rankinite
Crystallography of Rankinite
|Cell Parameters:||a = 10.55Å, b = 8.88Å, c = 7.85Å|
β = 119.58°
|Ratio:||a:b:c = 1.188 : 1 : 0.884|
|Unit Cell Volume:||V 639.57 Å³ (Calculated from Unit Cell)|
Optical Data of Rankinite
|RI values:||nα = 1.640 - 1.641 nβ = 1.644 nγ = 1.650|
|2V:||Measured: 64° , Calculated: 72° to 80°|
|Maximum Birefringence:||δ = 0.010|
Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Chemical Properties of Rankinite
|Simplified for copy/paste:||Ca3Si2O7|
|Essential elements:||Ca, O, Si|
|All elements listed in formula:||Ca, O, Si|
Relationship of Rankinite to other Species
|Related Minerals - Nickel-Strunz Grouping):|
|Related Minerals - Hey's Index Grouping:|
Other Names for Rankinite
|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 Rankinite
C. E. Tilley Tricalcium Disilicate (Rankinite), a New Mineral from Scawt Hill, Co. Antrim Mineralogical Magazine 1942 26 : 190-196
American Mineralogist (1942): 27: 720.
Mineralogical Journal: 8: 38-47.
Mineralogical Journal: 8: 240-246.
Physics and Chemistry of Minerals (1987): 14: 542.
Internet Links for Rankinite
Localities for Rankinite
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.