Tilleyite Mineral Data

[Content and History] [Recent Issues] [Back Issues] [Subscriptions] [Contacts]
See Also: [Diamond Crystals] [Excalibur Minerals] [Hudson Institute] [Minerals on CDROM]
Mineral News was founded some twenty years ago and has developed a following of
avid mineral collectors seeking timely information about new finds and other items
of interest to the collector community. Articles are solicited from collector and scientific authors.

General Tilleyite Information

Chemical Formula:

Ca5Si2O7(CO3)2

Composition:

Molecular Weight = 488.58 gm

Calcium 41.02 % Ca 57.39 % CaO

Silicon 11.50 % Si 24.60 % SiO₂

Carbon 4.92 % C 18.02 % CO₂

Oxygen 42.57 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca₅Si₂O₇(CO₃)₂

Environment:

In the contact metamorphic zone between igneous rocks and limestones, formed at low pressure and high temperature.

IMA Status:

Valid Species (Pre-IMA) 1933

Locality:

Crestmore quarry, 5 miles NW of Riverside, Riverside County, California. Link to MinDat.org Location Data.

Name Origin:

Named for Cecil Edgar Tilley (1894-1973), British petrologist, Cambridge University, Cambridge, England.

Name Pronunciation:

Tilleyite + Pronunciation

Synonym:

ICSD 14256

PDF 24-184

Tilleyite Image

Images:

Tilleyite

Comments: Opaque white fibrous tilleyite with blue calcite.
Location: Crestmore Quarry, Riverside County, California, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Tilleyite Crystallography

Axial Ratios:

a:b:c =1.4631:1:0.7428

Cell Dimensions:

a = 15.025, b = 10.269, c = 7.628, Z = 4; beta = 105.833° V = 1,132.29 Den(Calc)= 2.87

Crystal System:

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

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

By Intensity(I/I_o): 3.005(1), 3.095(0.85), 2.895(0.65),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
Keyboard
S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
Help on Above

Grice J D , The Canadian Mineralogist , 43 (2005) p.1489-1500, The structure of spurrite, tilleyite and scawtite,, and relationships to other silicate-carbonate minerals, Locality: Cornet Hill, Apuseni Mountains, Romania

View Additional jPOWD Structure files for Tilleyite
[1]

Physical Properties of Tilleyite

Cleavage:

{100} Perfect, {101} Good

Color:

Colorless, White.

Density:

2.84

Diaphaneity:

Transparent to Translucent

Streak:

white

Optical Properties of Tilleyite

Gladstone-Dale:

CI meas= -0.064 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= -0.053 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2208,KPDmeas= 0.2231,KC= 0.2097
Ncalc = 1.6

Optical Data:

Biaxial (+), a=1.612-1.617, b=1.632-1.635, g=1.652-1.654, bire=0.0370-0.0400, 2V(Calc)=88-90, 2V(Meas)=85-90. Dispersion r < v.

Calculated Properties of Tilleyite

Electron Density:

Bulk Density (Electron Density)=2.87 gm/cc
note: Specific Gravity of Tilleyite =2.87 gm/cc.

Fermion Index:

Fermion Index = 0.0066679407
Boson Index = 0.9933320593

Photoelectric:

PE_Tilleyite= 5.53 barns/electron
U=PE_Tilleyite x rElectron Density= 15.84 barns/cc.

Radioactivity:

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

Tilleyite Classification

Dana Class:

56.02.09.01 (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.08.2 09 - SILICATES (Germanates)

09.B - Sorosilicates

09.BE -Si2O7 groups with additional anions;

09.BE.08.2 Tilleyite Ca5Si2O7(CO3)2 P 2₁/a 2/m

Other Tilleyite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Heinrich65)

See Also:

Links to other databases for Tilleyite :
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

Search for Tilleyite using:

[ALTAVISTA] [AOL] [bing] [GeoScienceWorld] [HotBot] [Ixquick] [MAMMA] [MSN.COM] [Netscape] [Scirus] [Teoma] [Wikipedia] [YAHOO]

Visit our Advertisers for Tilleyite :

B & L Fine Minerals

Dan Weinrich Fine Minerals

Dan Weinrich Auctions

John Betts Fine Minerals

Lapis Mineral Journal

Mineral News

UV Tools

Wrights Rock Shop

Translate Tilleyite Mineral Data :

Ask about Tilleyite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Tilleyite

Ca5Si2O7(CO3)2
Dana No: 56.02.09.01 Strunz No: 09.BE.08.2
Locality:

Notes: