Macdonaldite
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About Macdonaldite
Formula:
BaCa4Si16O36(OH)2 · 10H2O
Colour:
White, colourless.
Lustre:
Vitreous, Silky
Hardness:
3½ - 4
Crystal System:
Orthorhombic
Name:
Named in honour of Gordon A. Macdonald (15 October 1911 – 20 June 1978), notable American volcanologist and Senior Professor of Geology at the University of Hawaii at the time of the description. His 1938 Ph.D. thesis "Geology of the Western Sierra Nevada Between Kings and San Joaquin Rivers, California" included this area.
Co-Type Localities:
ⓘ Big Creek, Rush Creek deposit, Big Creek-Rush Creek Mining District, Fresno Co., California, USA
ⓘ Esquire No. 7 claim, Big Creek, Rush Creek deposit, Big Creek-Rush Creek Mining District, Fresno Co., California, USA
ⓘ Esquire No. 1 claim, Rush Creek, Rush Creek deposit, Big Creek-Rush Creek Mining District, Fresno Co., California, USA
ⓘ Esquire No. 7 claim, Big Creek, Rush Creek deposit, Big Creek-Rush Creek Mining District, Fresno Co., California, USA
ⓘ Esquire No. 1 claim, Rush Creek, Rush Creek deposit, Big Creek-Rush Creek Mining District, Fresno Co., California, USA
This page provides mineralogical data about Macdonaldite.
Classification of Macdonaldite
Approved
8/H.38-50
9.EB.05
9 : SILICATES (Germanates)
E : Phyllosilicates
B : Double nets with 4- and 6-membered rings
9 : SILICATES (Germanates)
E : Phyllosilicates
B : Double nets with 4- and 6-membered rings
72.5.1.3
72 : PHYLLOSILICATES Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings
5 : Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings with corrugated and complex layers
72 : PHYLLOSILICATES Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings
5 : Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings with corrugated and complex layers
14.7.4
14 : Silicates not Containing Aluminum
7 : Silicates of Ba, Sr and Zn
14 : Silicates not Containing Aluminum
7 : Silicates of Ba, Sr and Zn
Physical Properties of Macdonaldite
Optical Data of Macdonaldite
Type:
Biaxial (+/-)
RI values:
nα = 1.518 nβ = 1.524 nγ = 1.530
2V:
Measured: 90° , Calculated: 88°
Max Birefringence:
δ = 0.012

Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Low
Dispersion:
weak
Chemical Properties of Macdonaldite
Formula:
BaCa4Si16O36(OH)2 · 10H2O
Common Impurities:
Ti,Al,Fe,Mn,Mg,Sr
Crystallography of Macdonaldite
Crystal System:
Orthorhombic
Cell Parameters:
a = 14.06 Å, b = 23.52 Å, c = 13.08 Å
Ratio:
a:b:c = 0.598 : 1 : 0.556
Unit Cell V:
4,325.44 ų (Calculated from Unit Cell)
Type Occurrence of Macdonaldite
Co-Type Localities:
ⓘ Big Creek, Rush Creek deposit, Big Creek-Rush Creek Mining District, Fresno Co., California, USA
ⓘ Esquire No. 7 claim, Big Creek, Rush Creek deposit, Big Creek-Rush Creek Mining District, Fresno Co., California, USA
ⓘ Esquire No. 1 claim, Rush Creek, Rush Creek deposit, Big Creek-Rush Creek Mining District, Fresno Co., California, USA
ⓘ Esquire No. 7 claim, Big Creek, Rush Creek deposit, Big Creek-Rush Creek Mining District, Fresno Co., California, USA
ⓘ Esquire No. 1 claim, Rush Creek, Rush Creek deposit, Big Creek-Rush Creek Mining District, Fresno Co., California, USA
Synonyms of Macdonaldite
Other Language Names for Macdonaldite
German:Macdonaldit
Russian:Макдональдит
Simplified Chinese:莫水硅钙钡石
Spanish:Macdonaldita
Traditional Chinese:莫水矽鈣鋇石
Common Associates
Associated Minerals Based on Photo Data:
Related Minerals - Nickel-Strunz Grouping
9.EB.05 | Rhodesite | KHCa2Si8O19 · 5H2O | Orth. mmm (2/m 2/m 2/m) |
9.EB.10 | Delhayelite | (Na,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3 · 18H2O | Orth. |
9.EB.10 | Hydrodelhayelite | KCa2AlSi7O17(OH)2 · 6H2O | Orth. |
9.EB.15 | Monteregianite-(Y) | (Na,K)6(Y,Ca)2Si16O38 · 10H2O | Mon. 2/m |
9.EB.20 | Carletonite | KNa4Ca4Si8O18(CO3)4(OH,F) · H2O | Tet. 4/mmm (4/m 2/m 2/m) : P4/mbm |
Related Minerals - Dana Grouping (8th Ed.)
72.5.1.1 | Rhodesite | KHCa2Si8O19 · 5H2O | Orth. mmm (2/m 2/m 2/m) |
72.5.1.2 | Monteregianite-(Y) | (Na,K)6(Y,Ca)2Si16O38 · 10H2O | Mon. 2/m |
72.5.1.4 | Delhayelite | (Na,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3 · 18H2O | Orth. |
72.5.1.5 | Hydrodelhayelite | KCa2AlSi7O17(OH)2 · 6H2O | Orth. |
Related Minerals - Hey's Chemical Index of Minerals Grouping
14.7.1 | Sanbornite | Ba2(Si4O10) | Orth. |
14.7.2 | Krauskopfite | BaSi2O5 · 3H2O | Mon. |
14.7.3 | Walstromite | BaCa2(Si3O9) | Tric. |
14.7.5 | Ericssonite | BaMn2+2Fe3+(Si2O7)O(OH) | Mon. 2/m : B2/m |
14.7.6 | Ericssonite-2O | BaMn2+2Fe3+(Si2O7)O(OH) | Orth. |
14.7.7 | Gillespite | BaFe2+Si4O10 | Tet. |
14.7.8 | Andrémeyerite | BaFe2+2(Si2O7) | Mon. |
14.7.9 | Pellyite | Ba2Ca(Fe,Mg)2Si6O17 | Orth. |
14.7.10 | Taikanite | Sr3BaMn2+2(Si4O12)O2 | Mon. |
14.7.11 | Willemite | Zn2SiO4 | Trig. 3 : R3 |
14.7.12 | Hemimorphite | Zn4Si2O7(OH)2 · H2O | Orth. mm2 : Imm2 |
14.7.13 | Zincsilite | Zn3(Si4O10)(OH)2 · 4H2O | Mon. |
14.7.14 | Hardystonite | Ca2Zn(Si2O7) | Tet. 4 2m : P4 21m |
14.7.15 | Petedunnite | Ca(Zn,Mn2+,Mg,Fe2+)Si2O6 | Mon. |
14.7.16 | Clinohedrite | CaZn(SiO4) · H2O | Mon. m : Bb |
14.7.17 | Junitoite | CaZn2Si2O7 · H2O | Orth. mm2 |
14.7.18 | Larsenite | PbZnSiO4 | Orth. mm2 : Pna21 |
14.7.19 | Esperite | PbCa2Zn3(SiO4)3 | Mon. 2/m : P21/b |
14.7.20 | Hodgkinsonite | Mn2+Zn2(SiO4)(OH)2 | Mon. |
14.7.21 | Gerstmannite | MnMgZn(SiO4)(OH)2 | Orth. |
14.7.22 | Gageite | Mn21(Si4O12)2O3(OH)20 | Mon. 2/m |
14.7.23 | Franklinfurnaceite | Ca2Fe3+Mn2+3Mn3+(Zn2Si2O10)(OH)8 | Mon. 2 : B2 |
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
References for Macdonaldite
Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
American Mineralogist (1965): 50: 314-340.
Internet Links for Macdonaldite
mindat.org URL:
https://www.mindat.org/min-2506.html
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External Links:
Mineral Dealers:
Localities for Macdonaldite
Locality List




All localities listed without proper references should be considered as questionable.
Italy | |
| Stoppa, F., Sharygin, V.V., and Cundari, A. (1997): Mineralogy and Petrology 61, 27-45.; Stoppa, F., & Schiazza, M. (2014). Extreme chemical conditions of crystallisation of Umbrian Melilitolites and wealth of rare, late stage/hydrothermal minerals. Central European Journal of Geosciences, 6(4), 549-564. |
USA | |
| Alfors, J.T., M.C. Stinson, R.A. Matthews & A. Pabst (1965), Seven new barium minerals from eastern Fresno County, California: American Mineralogist: 50: 318, 322-324; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 464. |
Stinson, Melvin Clarence & J.T. Alfors (1964), New minerals from Fresno County – I: California Division Mines & Geology Mineral Information Service.: 17: 238; Nickel & Nichols (1991), Mineral Reference Manual: 124: | |
| [Amer.Min.(1965) 50, 314-340; MinRec 33:161]; Canadian Mineralogist (2001): 39:1053-1058. |
Bob Walstrom, p.c. | |
| Nickel and Nichols (1991) Mineral Reference Manual, 123.; Jambor, J.L. and Roberts, A.C. (2002) New mineral names. American Mineralogist: 87: 765-768. |
| [MinRec 30:414] |
| Mineralogical Record: 34(2): 159-166 |
Big Creek, Rush Creek deposit, Big Creek-Rush Creek Mining District, Fresno Co., California, USA