Larnite Mineral Data

Larnite Mineral Data +

General Larnite Information

Chemical Formula:

Ca2SiO4

Composition:

Molecular Weight = 172.24 gm

Calcium 46.54 % Ca 65.12 % CaO

Silicon 16.31 % Si 34.88 % SiO₂

Oxygen 37.16 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca₂(SiO₄)

Environment:

Contact metamorphism of limestones.

IMA Status:

Valid Species (Pre-IMA) 1929

Locality:

Scawt Hill, near Larne, Co., Antrim, Ireland. Link to MinDat.org Location Data.

Name Origin:

Named after its locality.

Synonym:

ICSD 39006

PDF 33-302

Larnite Image

Images:

Larnite

Comments: Gray larnite masses in rock.
Location: Scawt Hills, Larne, County Antrim, Northern Ireland. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Images:

Larnite Paraspurrite

Comments: Violet-tinted gray crystalline pure paraspurrite mass with larnite veinlets.
Location: Near Darwin, Inyo County, California, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Larnite Crystallography

Axial Ratios:

a:b:c =0.8106:1:1.3727

Cell Dimensions:

a = 5.48, b = 6.76, c = 9.28, Z = 4; beta = 94.55° V = 342.69 Den(Calc)= 3.34

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/n

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 2.795(1), 2.744(0.95), 2.78(0.9),

Physical Properties of Larnite

Cleavage:

[100] Good

Color:

Colorless, Gray.

Density:

3.28

Diaphaniety:

Transparent to translucent

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Habit:

Tabular - Form dimensions are thin in one direction.

Hardness:

6 - Orthoclase

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Larnite

Gladstone-Dale:

CI meas= -0.045 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= -0.026 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2148,KPDmeas= 0.2187,KC= 0.2093

Optical Data:

Biaxial (+), a=1.707, b=1.715, g=1.73, bire=0.0230, 2V(Calc)=74, 2V(Meas)=large.

Calculated Properties of Larnite

Electron Density:

r_electron=3.34 gm/cc
note: r_Larnite=3.34 gm/cc.

Fermion Index

Fermion Index = 0.00842
Boson Index = 0.99158

Photoelectric:

PE_Larnite= 6.32 barns/electron
U=PE_Larnite x r_electron= 21.09 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Larnite is Not Radioactive

Larnite Classification

Dana Class:

51.5.1.1 (51)Nesosilicate Insular SiO4 Groups Only

(51.5)with cations in >[6] coordination

(51.5.1)Dana Group

51.5.1.1 Larnite Ca2SiO4 P 2₁/n 2/m

Strunz Class:

VIII/A.07-30 VIII - Silicates

VIII/A - Nesosilicates with [SiO4]4-groups, cations of octahedral orientation [6]

VIII/A.07 - Larnite series

VIII/A.07-10 Merwinite Ca3Mg(SiO4)2 P 2₁/a 2/m

VIII/A.07-20 Bredigite Ca7Mg(SiO4)4 P 2nn mm2

VIII/A.07-30 Larnite Ca2SiO4 P 2₁/n 2/m

Other Larnite Information

References:

NAME( Ford32) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Heinrich65)

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Print or Cut-and-Paste your Larnite Specimen Label here :

Larnite

Ca2SiO4
Dana No: 51.5.1.1 Strunz No: VIII/A.07-30
Locality:

Notes: