Macdonaldite Mineral Data

General Macdonaldite Information

Chemical Formula:

BaCa4[Si16O36(OH)2]•10(H2O)

Composition:

Molecular Weight = 1,537.15 gm

Barium 8.93 % Ba 9.97 % BaO

Calcium 10.43 % Ca 14.59 % CaO

Silicon 29.23 % Si 62.54 % SiO₂

Hydrogen 1.44 % H 12.89 % H₂O

Oxygen 49.96 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

BaCa₄Si₁₆O₃₆(OH)₂•10(H₂O)

Environment:

Sanbornite-bearing metamorphic rocks near a granodiorite contact.

IMA Status:

Approved IMA 1965

Locality:

Big Creek - Rush Creek sanbornite deposit, 5 miles NE of Trimmer, Fresno Co., California. Link to MinDat.org Location Data.

Name Origin:

Named for Grodon Andrew Macdonald (1911-1978), American volcanologist, University of Hawaii.

Name Pronunciation:

Macdonaldite + Pronunciation

Synonym:

ICSD 23566

PDF 18-163

Macdonaldite Image

Images:

Macdonaldite

Comments: Bright white flattened radial macdonaldite aggregate on quartz.
Location: Rush Creek, Fresno County, California, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Macdonaldite Crystallography

Axial Ratios:

a:b:c =0.5977:1:0.5561

Cell Dimensions:

a = 14.06, b = 23.52, c = 13.08, Z = 4; V = 4,325.44 Den(Calc)= 2.36

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: C mcm

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

By Intensity(I/I_o): 6.5(1), 4.36(0.8), 6.3(0.5),

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

Cannillo E , Rossi G , Ungaretti L , Atti della Accademia Nazionale dei Lincei , 45 (1968) p.399-414, The crystal structure of macdonaldite, Locality: Fresno County, California, USA, Note: x(Si4) corrected

Physical Properties of Macdonaldite

Cleavage:

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

Color:

Colorless, White.

Density:

2.27

Diaphaneity:

Transparent

Habit:

Acicular - Occurs as needle-like crystals.

Hardness:

3.5-4 - Copper Penny-Fluorite

Luster:

Vitreous - Silky

Streak:

white

Optical Properties of Macdonaldite

Gladstone-Dale:

CI meas= -0.062 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= -0.022 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.222,KPDmeas= 0.2308,KC= 0.2173
Ncalc = 1.49 - 1.51

Optical Data:

Biaxial (+/-), a=1.518, b=1.524, g=1.53, bire=0.0120, 2V(Calc)=88, 2V(Meas)=90.

Calculated Properties of Macdonaldite

Electron Density:

Bulk Density (Electron Density)=2.35 gm/cc
note: Specific Gravity of Macdonaldite =2.36 gm/cc.

Fermion Index:

Fermion Index = 0.02
Boson Index = 0.98

Photoelectric:

PE_Macdonaldite= 38.38 barns/electron
U=PE_Macdonaldite x rElectron Density= 90.28 barns/cc.

Radioactivity:

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

Macdonaldite Classification

Dana Class:

72.05.01.03 (72)Phyllosilicate Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings

(72.05)with corrugated and complex layers

(72.05.01)Rhodesite group

72.05.01.01 Rhodesite KHCa2Si8O19•5(H2O) Pmam 2/m 2/m 2/m

72.05.01.02 Monteregianite-(Y) (Na,K)6(Y,Ca)2Si16O38•10(H2O) P 2₁/m 2/m

72.05.01.03 Macdonaldite BaCa4[Si16O36(OH)2]•10(H2O) C mcm 2/m 2/m 2/m

72.05.01.04 Delhayelite (Na,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3•18(H2O) Pnmm 2/m 2/m 2/m

72.05.01.05 Hydrodelhayelite KCa2AlSi7O17(OH)2•6(H2O) Pnm21 mm2

72.05.01.06 Seidite-(Ce)! Na4(Ce,Sr)2{Ti(OH)2(Si8O18)}(O,OH,F)4•5(H2O) C/2c 2/m

Strunz Class:

09.EB.05 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.EB -Double nets with 4- and 6-membered rings

09.EB.05 Macdonaldite BaCa4[Si16O36(OH)2]•10(H2O) C mcm 2/m 2/m 2/m

09.EB.05 Rhodesite KHCa2Si8O19•5(H2O) Pmam 2/m 2/m 2/m

Other Macdonaldite Information

References:

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

See Also:

Links to other databases for Macdonaldite :
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 Macdonaldite using:

[AOL] [Bing] [Dog Pile] [GeoScienceWorld] [HotBot] [Ixquick] [Lycos] [MAMMA] [Scirus] [Teoma] [WebCrawler] [Wikipedia] [YAHOO]

Visit our Advertisers for Macdonaldite :

A Bijoux Google Search for Macdonaldite
Adam's Minerals Google Search for Macdonaldite
Cape Minerals Google Search for Macdonaldite
Dakota Matrix Minerals Google Search for Macdonaldite
Excalibur Mineral Corp. Google Search for Macdonaldite
Exceptional Minerals Google Search for Macdonaldite
John Betts Fine Minerals Search for Macdonaldite
McDougall Minerals Google Search for Macdonaldite
Mineral News Website Link
Rock and Mineral Shows Google Search for Macdonaldite
Weinrich Minerals, Inc. Google Search for Macdonaldite

Ask about Macdonaldite 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 Macdonaldite Specimen Label here :

Macdonaldite

BaCa4[Si16O36(OH)2]•10(H2O)
Dana No: 72.05.01.03 Strunz No: 09.EB.05
Locality:

Notes: