Larnite (original) (raw)

A valid IMA mineral species - grandfathered

About LarniteHide

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Colour:

White, gray, colorless in thin section

Specific Gravity:

3.28 - 3.33

Crystal System:

Monoclinic

Name:

The material was first identified from Portland cement and named belite by Törneborn in 1897. The natural substance, a mineral, was named by Tilley in 1929 after the town of Larne, North Ireland, UK. The town is near the type locality of Scawt Hill.

The high-temperature, monoclinic polymorph of Calcio-Olivine.

Larnite crystallizes at high temperatures. It occurs in limestones or chalk zones in contact with molten basaltic rocks. Larnite is stable in the range of 520° to 670° C; otherwise, it is only metastable at lower temperatures and inverts to its low-temperature polymorph, Calcio-Olivine, when shocked.

An important phase (Belite, β-C2S) in cement clinker.
Five polymorphs of Ca2SiO4 are known; some are stabilised by impurities.

Larnite is NOT a member of the olivine group.

Unique IdentifiersHide

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Long-form identifier:

mindat:1:1:2333:3

97fbc9ff-300b-44de-b104-e1a9dba51805

IMA Classification of LarniteHide

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Approved, 'Grandfathered' (first described prior to 1959)

Type description reference:

Classification of LarniteHide

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9.AD.05

9 : SILICATES (Germanates)
A : Nesosilicates
D : Nesosilicates without additional anions; cations in [6] and/or greater coordination

51.5.1.1

51 : NESOSILICATES Insular SiO4 Groups Only
5 : Insular SiO4 Groups Only with cations in >[6] coordination

14.5.6

14 : Silicates not Containing Aluminum
5 : Silicates of Ca

Mineral SymbolsHide

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As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.

Physical Properties of LarniteHide

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Transparency:

Transparent, Translucent

Colour:

White, gray, colorless in thin section

Cleavage:

Distinct/Good
{100} good;
{010} imperfect

Density:

3.28 - 3.33 g/cm3 (Measured) 3.326 g/cm3 (Calculated)

Optical Data of LarniteHide

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RI values:

_n_α = 1.700 - 1.715 _n_β = 1.715 - 1.723 _n_γ = 1.725 - 1.740

2V:

Measured: 60° to 63°, Calculated: 74°

δ = 0.025

Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.

Chemistry of LarniteHide

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Common Impurities:

Al,Fe,Mg,Na,H2O,C,P

Crystallography of LarniteHide

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Crystal System:

Monoclinic

Class (H-M):

2/m - Prismatic

Cell Parameters:

a = 5.502(1) Å, b = 6.745(1) Å, c = 9.297(1) Å
β = 94.59(2)°

Ratio:

a:b:c = 0.816 : 1 : 1.378

Unit Cell V:

343.91 ų (Calculated from Unit Cell)

Twinning:

Common. Polysynthetic parallel to {100}.

Comment:

Space Group: P21/n:

Crystal StructureHide

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X-Ray Powder DiffractionHide

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Powder Diffraction Data:

Comments:

Synthetic. (ICDD 9-351).

Geological EnvironmentHide

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Geological Setting:

Metamorphosed sedimentary carbonate formations in contact with basaltic rocks.

Type Occurrence of LarniteHide

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Geological Setting of Type Material:

contact metamorphic terranes involving sedimentary carbonate rocks.

Associated Minerals at Type Locality:

Reference:

Tilley, C.E. (1929) On larnite (calcium orthosilicate, a new mineral) and its associated minerals from the limestone contact-zone of Scawt Hill, Co. Antrim. Mineralogical Magazine: 22: 77-86.

Synonyms of LarniteHide

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Other Language Names for LarniteHide

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Simplified Chinese:斜硅钙石

Traditional Chinese:斜矽鈣石

Common AssociatesHide

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Associated Minerals Based on Photo Data:

Related Minerals - Strunz-mindat GroupingHide

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Other InformationHide

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Health Risks:

No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

Internet Links for LarniteHide

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References for LarniteHide

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Reference List:

Martínez-Frías, J., Benito, R., Wilson, G., Delgado, A., Boyd, T., and Marti, K. (2004) Analysis and chemical composition of larnite-rich ultrarefractory materials. Journal of Materials Processing Technology: 147: 204–210.

Brenker, F.E., Vincze, L., Vekemans, B., Nasdala, L., Stachel, T., Vollmer, C., Kersten, M., Somogyi, A., Adams, F., Joswig, W., Harris, J.W. (2005) Detection of a Ca-rich lithology in the Earth's deep (>300 km) convecting mantle. Earth and Planetary Science Letters: 236(3-4): 579-587.

Xiong, Z., Liu, X., Shieh, S.R., Wang, S., Chang, L., Tang, J., Hong, X., Zhang, Z., Wang, H. (2016) Some thermodynamic properties of larnite (β-Ca2SiO4) constrained by High T/P experiment and/or theoretical simulation. American Mineralogist: 101: 277-288.

Plana-Ruiz, Sergi, Götz, Emilia, Neumann, Thomas, Schwesig, Peter, Kolb, Ute (2024) Three-dimensional electron diffraction on clinkers: the belite α′ H incommensurate modulated structure. Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials, 80 (2) 105-116 doi:10.1107/s205252062400146x

Localities for LarniteHide

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This 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.

Locality ListHide

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- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for references and further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.