Killalaite Mineral Data

General Killalaite Information

Chemical Formula:

2Ca3Si2O7•(H2O)

Composition:

Molecular Weight = 594.82 gm

Calcium 40.43 % Ca 56.57 % CaO

Silicon 18.89 % Si 40.41 % SiO₂

Hydrogen 0.34 % H 3.03 % H₂O

Oxygen 40.35 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca₆Si₄O₁₄•(H₂O)

Environment:

A secondary mineral in cavities and veins in hydrothermally altered and thermally metamorphosed limestones.

IMA Status:

Approved IMA 1974

Locality:

From near Inishcrone, along the east shore of Killala Bay, Co. Sligo, and at Carneal, Co. Antrim, Ireland. Link to MinDat.org Location Data.

Name Origin:

Named for the locality

Name Pronunciation:

Killalaite + Pronunciation

Synonym:

ICSD 200124

PDF 29-332

Killalaite Image

Images:

Killalaite

Comments: B&W PPL image of killalaite crystals in a vein of calcite. MinMag v39:544.
Location: Thermally metamorphosed limestone near Inishcrone, along the eastern shore of Killala Bay, Co. Sligo, Ireland. Scale: Crystal Size 0.5 mm.
© Mineralogical Magazine

Killalaite Crystallography

Axial Ratios:

a:b:c =0.4403:1:0.4405

Cell Dimensions:

a = 6.807, b = 15.459, c = 6.811, Z = 2; beta = 97.76° V = 710.15 Den(Calc)= 2.78

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 2₁/m

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

By Intensity(I/I_o): 2.824(1), 3.03(0.8), 2.724(0.6),

Physical Properties of Killalaite

Cleavage:

{100} Perfect, {010} Good, {001} Good

Color:

Colorless, White.

Density:

2.94

Streak:

white

Optical Properties of Killalaite

Gladstone-Dale:

CI meas= -0.019 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.078 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2297,KPDmeas= 0.2172,KC= 0.2131
Ncalc = 1.59 - 1.63

Optical Data:

Biaxial (-), a=1.635, g=1.642, bire=0.0070, 2V(Meas)=26.

Calculated Properties of Killalaite

Electron Density:

Bulk Density (Electron Density)=2.95 gm/cc
note: Specific Gravity of Killalaite =2.94 gm/cc.

Fermion Index:

Fermion Index = 0.0095600872
Boson Index = 0.9904399128

Photoelectric:

PE_Killalaite= 5.67 barns/electron
U=PE_Killalaite x rElectron Density= 16.69 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Killalaite is Not Radioactive

Killalaite Classification

Dana Class:

56.02.09.02 (56)Sorosilicate Si2O7 Groups and O, OH, F. and H2O

(56.02)with cations in [4] and/or >[4] coordination

(56.02.09)Tilleyite - Killalaite group

56.02.09.01 Tilleyite Ca5Si2O7(CO3)2 P 2₁/a 2/m

56.02.09.02 Killalaite 2Ca3Si2O7•(H2O) P 2₁/m 2/m

56.02.09.03 Foshallasite? Ca3Si2O7•3(H2O) Mono

Strunz Class:

09.BE.85 09 - SILICATES (Germanates)

09.B - Sorosilicates

09.BE -Si2O7 groups with additional anions;

09.BE.85 Killalaite 2Ca3Si2O7•(H2O) P 2₁/m 2/m

Other Killalaite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Killalaite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - WWW-MINCRYST

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

Killalaite

2Ca3Si2O7•(H2O)
Dana No: 56.02.09.02 Strunz No: 09.BE.85
Locality:

Notes:

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