Merwinite
A valid IMA mineral species - grandfathered
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About Merwinite
Herbert Eugene Merwin
Formula:
Ca3Mg(SiO4)2
Colour:
White, colorless, light green, light gray green
Lustre:
Vitreous, Sub-Vitreous, Greasy
Hardness:
6
Specific Gravity:
3.15 - 3.32
Crystal System:
Monoclinic
Name:
Named in 1921 by Esper S. Larsen I and George Faust for Herbert Eugene Merwin [1878-1963], mineralogist Carnegie Institute, Washington, DC.
This page provides mineralogical data about Merwinite.
Unique Identifiers
Mindat ID:
2656
Long-form identifier:
mindat:1:1:2656:3
Similar Names
| Merlinite | A synonym of 'Chalcedony' |
IMA Classification of Merwinite
Approved, 'Grandfathered' (first described prior to 1959)
Classification of Merwinite
9.AD.15
9 : SILICATES (Germanates)
A : Nesosilicates
D : Nesosilicates without additional anions; cations in [6] and/or greater coordination
9 : SILICATES (Germanates)
A : Nesosilicates
D : Nesosilicates without additional anions; cations in [6] and/or greater coordination
51.4.2.1
51 : NESOSILICATES Insular SiO4 Groups Only
4 : Insular SiO4 Groups Only with cations in [6] and >[6] coordination
51 : NESOSILICATES Insular SiO4 Groups Only
4 : Insular SiO4 Groups Only with cations in [6] and >[6] coordination
14.6.11
14 : Silicates not Containing Aluminum
6 : Silicates of Ca with alkali or Mg or both
14 : Silicates not Containing Aluminum
6 : Silicates of Ca with alkali or Mg or both
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Mw | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Mw | Siivolam & Schmid (2007) | Siivolam, J. and Schmid, R. (2007) Recommendations by the IUGS Subcommission on the Systematics of Metamorphic Rocks: List of mineral abbreviations. Web-version 01.02.07. IUGS Commission on the Systematics in Petrology. download |
| Mw | Whitney & Evans (2010) | Whitney, D.L. and Evans, B.W. (2010) Abbreviations for names of rock-forming minerals. American Mineralogist, 95, 185–187 doi:10.2138/am.2010.3371 |
| Mer | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of Merwinite
Vitreous, Sub-Vitreous, Greasy
Transparency:
Transparent
Colour:
White, colorless, light green, light gray green
Streak:
White
Hardness:
6 on Mohs scale
Hardness Data:
Measured
Tenacity:
Brittle
Cleavage:
Distinct/Good
{100}
{100}
Fracture:
Irregular/Uneven
Density:
3.15 - 3.32 g/cm3 (Measured) 3.32 g/cm3 (Calculated)
Optical Data of Merwinite
Type:
Biaxial (+)
RI values:
nα = 1.706 - 1.708 nβ = 1.711 - 1.712 nγ = 1.718 - 1.724
2V:
Measured: 65° to 74°, Calculated: 62° to 82°
Birefringence:
0.014
Max. Birefringence:
δ = 0.012 - 0.016
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Moderate
Dispersion:
r > v
Pleochroism:
Non-pleochroic
Chemistry of Merwinite
Mindat Formula:
Ca3Mg(SiO4)2
Element Weights:
Elements listed:
Common Impurities:
Al,Fe
Crystallography of Merwinite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Cell Parameters:
a = 13.29 Å, b = 5.3 Å, c = 9.35 Å
β = 92.09°
β = 92.09°
Ratio:
a:b:c = 2.508 : 1 : 1.764
Unit Cell V:
658.15 ų (Calculated from Unit Cell)
Z:
4
Twinning:
Polysynthetic {100}
Comment:
Distorted glaserite structure, not an olivine.
Crystal Structure
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0000294 | Merwinite | Moore P B, Araki T (1972) Atomic arrangement of merwinite, Ca3Mg[SiO4]2, an unusual dense-packed structure of geophysical interest American Mineralogist 57 1355-1374 |  | 1972 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Loading XRD data...
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 4.70 Å | (50) |
| 2.752 Å | (40) |
| 2.674 Å | (100) |
| 2.652 Å | (50) |
| 2.452 Å | (80) |
| 2.211 Å | (40) |
| 2.031 Å | (30) |
| 1.909 Å | (30) |
Comments:
Natural material, also 35-591 (synthetic)
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 31 : Thermally altered carbonate, phosphate, and iron formations | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 51 : Pyrometamorphic minerals (see also #54 and #56) | <0.36 |
Type Occurrence of Merwinite
Geological Setting of Type Material:
High temperature, low pressure contact metamorphic zones with marbles.
Associated Minerals at Type Locality:
Synonyms of Merwinite
Other Language Names for Merwinite
Common Associates
Associations Based on Photo Data:
| 12 photos of Merwinite associated with Vesuvianite | Ca19Fe3+Al4(Al6Mg2)(◻4)◻[Si2O7]4[(SiO4)10]O(OH)9 |
| 7 photos of Merwinite associated with Calcite | CaCO3 |
| 6 photos of Merwinite associated with Gehlenite | Ca2Al[AlSiO7] |
| 3 photos of Merwinite associated with Afwillite | Ca3[SiO4][SiO2(OH)2] · 2H2O |
| 3 photos of Merwinite associated with Perovskite | CaTiO3 |
| 2 photos of Merwinite associated with Clinozoisite | (CaCa)(AlAlAl)O[Si2O7][SiO4](OH) |
| 2 photos of Merwinite associated with Tilleyite | Ca5(Si2O7)(CO3)2 |
| 2 photos of Merwinite associated with Hillebrandite | Ca2(SiO3)(OH)2 |
| 2 photos of Merwinite associated with Grossular | Ca3Al2(SiO4)3 |
| 2 photos of Merwinite associated with Foshagite | Ca4(Si3O9)(OH)2 |
Related Minerals - Strunz-mindat Grouping
| 9.AD. | Adrianite | Ca12(Al4Mg3Si7)O32Cl6 |
| 9.AD.05 | Larnite | Ca2SiO4 |
| 9.AD.10 | Calcio-olivine | Ca2SiO4 |
| 9.AD.20 | Bredigite | Ca7Mg(SiO4)4 |
| 9.AD.25 | Midbarite | Ca3Mg2(V5+2Si)O12 |
| 9.AD.25 | Menzerite-(Y) | (Y2Ca)Mg2(SiO4)3 |
| 9.AD.25 | Uvarovite | Ca3Cr3+2(SiO4)3 |
| 9.AD.25 | Eltyubyuite | Ca12Fe3+10Si4O32Cl6 |
| 9.AD.25 | Eringaite | Ca3Sc2(SiO4)3 |
| 9.AD.25 | Henritermierite | Ca3Mn3+2(SiO4)2[◻(OH)4] |
| 9.AD.25 va | 'Hydrougrandite' | (Ca,Mg,Fe2+)3(Fe3+,Al)2[(OH)4(SiO4)2] |
| 9.AD.25 | Calderite | Mn2+3Fe3+2(SiO4)3 |
| 9.AD.25 | Nikmelnikovite | Ca12(Fe2+Fe3+3Al3◻)[SiO4]6[◻(OH)4]5◻4 |
| 9.AD.25 | Hutcheonite | Ca3Ti2(SiO4)(AlO4)2 |
| 9.AD.25 | Wadalite | (Ca,Mg)6(Al,Fe3+)4((Si,Al)O4)3O4Cl3 |
| 9.AD.25 | Rubinite | Ca3Ti3+2(SiO4)3 |
| 9.AD.25 | Kerimasite | Ca3Zr2(SiO4)(Fe3+O4)2 |
| 9.AD.25 | Holtstamite | Ca3Al2(SiO4)2[◻(OH)4] |
| 9.AD.25 | Spessartine | Mn2+3Al2(SiO4)3 |
| 9.AD.25 | Toturite | Ca3Sn2(SiO4)(Fe3+O4)2 |
| 9.AD.25 | Kimzeyite | Ca3Zr2(SiO4)(AlO4)2 |
| 9.AD.25 | 'Khoharite' | Mg3Fe3+2(SiO4)3 |
| 9.AD.25 | Irinarassite | Ca3Sn2(SiO4)(AlO4)2 |
| 9.AD.25 | Knorringite | Mg3Cr3+2(SiO4)3 |
| 9.AD.25 | Goldmanite | Ca3V3+2(SiO4)3 |
| 9.AD.25 | 'Blythite' | Mn2+3Mn3+2[SiO4]3 |
| 9.AD.25 | 'Skiagite' | Fe2+3Fe3+2[SiO4]3 |
| 9.AD.25 | 'UM1984-37-SiO:CrMn' | Mn2+3Cr3+2(SiO4)3 |
| 9.AD.25 | Almandine | Fe2+3Al2(SiO4)3 |
| 9.AD.25 va | 'Yamatoite' | (Mn2+,Ca)3(V3+,Al)2(SiO4)3 |
| 9.AD.25 | Momoiite | Mn2+3V3+2(SiO4)3 |
| 9.AD.25 | Grossular | Ca3Al2(SiO4)3 |
| 9.AD.25 | Andradite | Ca3Fe3+2(SiO4)3 |
| 9.AD.25 | Morimotoite | Ca3(TiFe2+)(SiO4)3 |
| 9.AD.25 | Majorite | Mg3(MgSi)(SiO4)3 |
| 9.AD.25 | Pyrope | Mg3Al2(SiO4)3 |
| 9.AD.25 | Schorlomite | Ca3Ti2(SiO4)(Fe3+O4)2 |
| 9.AD.30 | Hafnon | Hf(SiO4) |
| 9.AD.30 | Zircon | Zr(SiO4) |
| 9.AD.30 | Coffinite | U(SiO4) · nH2O |
| 9.AD.30 | Thorite | Th(SiO4) |
| 9.AD.30 va | 'Auerlite' | near Th(Si,P)O4 |
| 9.AD.30 | Stetindite-(Ce) | Ce4+SiO4 |
| 9.AD.35 | 'Tombarthite-(Y)' | Y4(Si,H4)4O12-x(OH)4+2x |
| 9.AD.35 | Huttonite | ThSiO4 |
| 9.AD.40 | Eulytine | Bi4(SiO4)3 |
| 9.AD.45 | Reidite | Zr(SiO4) |
| 9.AD.55 | Jeffbenite | Mg3Al2Si3O12 |
Fluorescence of Merwinite
Not fluorescent
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.
Merwinite in petrology
An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.
Internet Links for Merwinite
mindat.org URL:
https://www.mindat.org/min-2656.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Merwinite
Reference List:
Larsen, Esper S., Foshag, William F. (1921) Merwinite, a new calcium magnesium orthosilicate from Crestmore, California. American Mineralogist, 6 (10) 143-147
Phemister, James, Nurse, R. W., Bannister, F. A. (1942) Merwinite as an artificial mineral. Mineralogical Magazine and Journal of the Mineralogical Society, 26 (177) 225-230 doi:10.1180/minmag.1942.026.177.03
Osborn, E. F. (1943) The compound merwinite and its stability-relations in the system CaO—MgO—SiO2. Transactions, American Geophysical Union, 24 (1) 251 doi:10.1029/tr024i001p00251-1
Roy, Della M. (1956) Subsolidus data for the join Ca2SiO4—CaMgSiO4 and the stability of merwinite. Mineralogical Magazine and Journal of the Mineralogical Society, 31 (233) 187-194 doi:10.1180/minmag.1956.031.233.07
Nagai, Shoichiro, Arai, Yasuo (1959) Synthesis of Merwinite and Acid Solubilities of the Products. The Journal of the Society of Chemical Industry, Japan, 62. 1348-1352 doi:10.1246/nikkashi1898.62.9_1348
GUTT, W. (1965) The System Dicalcium Silicate–Merwinite. Nature, 207 (4993). 184-185 doi:10.1038/207184a0
SCHLAUDT, C. M., ROY, DELLA M. (1966) The Join Ca2SiO4-CaMgSiO4. Journal of the American Ceramic Society, 49 (8). 430-432 doi:10.1111/j.1151-2916.1966.tb15410.x
Basson, G. R. (1966) Note on the crystallization of merwinite from glass of åkermanite composition. Mineralogical Magazine and Journal of the Mineralogical Society, 35 (274) 873-875 doi:10.1180/minmag.1966.035.274.10
BIGGAR, G. M., O'HARA, M. J. (1970) Melting of Forsterite, Monticellite, Merwinite, Spinel, and Periclase Assemblages. Journal of the American Ceramic Society, 53 (10). 534-537 doi:10.1111/j.1151-2916.1970.tb15959.x
Moore, Paul Brian, Araki, Takaharu (1972) Atomic arrangement of merwinite, Ca3Mg[SiO4]2, an unusual dense-packed structure of geophysical interest. American Mineralogist, 57 (9-10) 1355-1374
Nawaz, Rab, Preston, and John (1974) Optical orientation and twinning of merwinite: A restudy. American Mineralogist, 59 (9-10) 1117-1120
Localities for Merwinite
Showing 30 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Brazil | |
| Zedgenizov et al. (2014) |
Bulgaria | |
| I. Kostov et al. (1964) |
Canada | |
| Chatterjee (1980) |
| Rosa et al. (2010) |
China | |
| Xiangzhen Meng and Meifang Zhao (1985) |
| Shouquan Zhu (1994) |
Georgia | |
| Galuskina et al. (2015) +1 other reference |
Germany | |
| Schnorrer et al. (2001) |
Israel | |
| Kahlenberg et al. (2019) |
| Sharygin et al. (2008) |
Jordan | |
| Pitty et al. (2010) |
Middle East | |
| Gross (1977) | |
Poland | |
| Warchulski et al. (2015) |
| Warchulski et al. (2015) |
Russia | |
| American Mineralogist |
| Pavel M. Kartashov (n.d.) +2 other references |
| Sokol et al. (2019) +3 other references |
| Mineralogical Society of America - ... +1 other reference |
| Victor V. Sharygin analytical data |
UK | |
| Henmi et al. (1973) |
| Tilley (1947) |
| Agrell (1965) +2 other references |
USA | |
| Woodford et al. (1941) |
| Woodford et al. (1941) | |
| Woodford et al. (1941) +1 other reference |
| Gobla (2012) |
| NMGS 21st Field Conference |
| Smith (1991) |
| Bridge (1966) |
| Smith (1991) |
Quick NavTopAbout MerwiniteUnique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatFluorescence Other InformationMerwinite in petrologyInternet Links References Localities Locality List
Crestmore quarries, Crestmore, Jurupa Valley, Riverside County, California, USA