Molybdophyllite
A valid IMA mineral species - grandfathered
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About Molybdophyllite
Formula:
Pb8Mg9[Si10O28(OH)8O2(CO3)3] · H2O
Originally assumed to be "Pb2Mg2Si2O7(OH)2."
Colour:
Colourless, pale grey, pale yellow, very pale green
Lustre:
Pearly
Hardness:
3 - 4
Specific Gravity:
4.652 (Calculated)
Crystal System:
Monoclinic
Name:
From the Greek molybdos, for lead, and phyllos (φύλλον), for leaf, in allusion to its lead content and foliated habit.
Molybdophyllite has an OD (order-disorder) structure. A trigonal and a monoclinic polytype have been derived by the OD approach. The crystal structure of the latter (C2) has been determined.
Closely related to britvinite.
Closely related to britvinite.
Unique Identifiers
Mindat ID:
2735
Long-form identifier:
mindat:1:1:2735:5
Similar Names
| Molybdophyllite-18 Å | A synonym of Britvinite |
IMA Classification of Molybdophyllite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Pb2+8Mg9[Si10O30(OH)8(CO3)3]·H2O
Classification of Molybdophyllite
9.HH.25
9 : SILICATES (Germanates)
H : Unclassified silicates
H : With Pb
9 : SILICATES (Germanates)
H : Unclassified silicates
H : With Pb
78.5.7.1
78 : Unclassified Silicates
5 :
78 : Unclassified Silicates
5 :
14.13.4
14 : Silicates not Containing Aluminum
13 : Silicates of Pb
14 : Silicates not Containing Aluminum
13 : Silicates of Pb
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Mdp | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Molybdophyllite
Pearly
Transparency:
Transparent, Translucent
Colour:
Colourless, pale grey, pale yellow, very pale green
Streak:
White
Hardness:
3 - 4 on Mohs scale
Tenacity:
Flexible
Cleavage:
Perfect
Parallel to the pseudohexagonal (0001) plane.
Parallel to the pseudohexagonal (0001) plane.
Fracture:
Irregular/Uneven
Comment:
Only a little more brittle than mica.
Density:
4.652 g/cm3 (Calculated)
Optical Data of Molybdophyllite
Type:
Biaxial (-)
Comments:
Pseudo-uniaxial (-) optics: ω = 1.815, ε = 1.761. Modern optical analysis given in Kolitsch et al. (2012).
Chemistry of Molybdophyllite
Mindat Formula:
Pb8Mg9[Si10O28(OH)8O2(CO3)3] · H2O
Originally assumed to be "Pb2Mg2Si2O7(OH)2."
Originally assumed to be "Pb2Mg2Si2O7(OH)2."
Element Weights:
Common Impurities:
Al,Na,K,H2O
Crystallography of Molybdophyllite
Crystal System:
Monoclinic
Class (H-M):
2 - Sphenoidal
Space Group:
B2
Setting:
C2
Cell Parameters:
a = 16.232(6) Å, b = 9.373(2) Å, c = 14.060(3) Å
β = 97.36°
β = 97.36°
Ratio:
a:b:c = 1.732 : 1 : 1.5
Unit Cell V:
2121.5 ų
Z:
2
Morphology:
Platy aggregates, embedded in matrix.
Comment:
Pseudohexagonal.
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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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) |
|---|---|---|---|---|---|---|---|
| 0018886 | Molybdophyllite | Kolitsch U, Merlino S, Holtstam D (2012) Molybdophyllite: crystal chemistry, crystal structure, OD character and modular relationships with britvinite Sample 221135 Mineralogical Magazine 76 493-512 | 2012 | Harstigen, Filipstad, Sweden | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 13.8 Å | (100) |
| 4.60 Å | (90) |
| 2.67 Å | (70) |
| 3.80 Å | (60) |
| 3.04 Å | (60) |
| 2.95 Å | (60) |
| 1.762 Å | (60) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 31 : Thermally altered carbonate, phosphate, and iron formations | |
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] |
Type Occurrence of Molybdophyllite
Other Language Names for Molybdophyllite
Common Associates
Associations Based on Photo Data:
| 6 photos of Molybdophyllite associated with Hausmannite | Mn2+Mn3+2O4 |
| 5 photos of Molybdophyllite associated with Calcite | CaCO3 |
| 1 photo of Molybdophyllite associated with Pinakiolite | (Mg,Mn2+)2Mn3+(BO3)O2 |
Related Minerals - Strunz-mindat Grouping
| 9.HH.05 | Macquartite | Cu2Pb7(CrO4)4(SiO4)2(OH)2 |
| 9.HH.10 | Luddenite | Cu2Pb2Si5O14 · 4H2O |
| 9.HH.15 | Creaseyite | Pb2Cu2Fe3+2(Si4.67Al0.33)O15.33(OH)3 · H2O |
| 9.HH.20 | Plumbotsumite | Pb13(CO3)6(Si10O27) · 3H2O |
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.
Internet Links for Molybdophyllite
mindat.org URL:
https://www.mindat.org/min-2735.html
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Please feel free to link to this page.
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References for Molybdophyllite
Reference List:
Aminoff, G. (1918) Röntgenographische Ermittelung der Symmetrie und des Elementes po des Molybdophyllits. Geologiska Föreningen i Stockholm Förhandlingar, 40 (7) 923-938 doi:10.1080/11035891809444851
Localities for Molybdophyllite
Showing 4 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.
Namibia | |
| Dunn (1991) |
Sweden (TL) | |
| Aminoff (1918) +2 other references |
| Nysten (1984) +2 other references |
UK | |
| Turner et al. (2010) |
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Långban Mine, Långban Ore District, Filipstad, Värmland County, Sweden