Bobmeyerite
A valid IMA mineral species
This page kindly sponsored by Robert Meyer
About Bobmeyerite
Bob Meyer
Formula:
Pb4(Al3Cu)(Si4O12)(S0.5Si0.5O4)(OH)7Cl(H2O)3
The above formula is from the original description; the formula from the IMA proposal: Pb4Al4(Si4O12)(OH)11Cl(H2O)
Colour:
colorless to white
Lustre:
Vitreous
Specific Gravity:
4.381 (Calculated)
Crystal System:
Orthorhombic
Name:
Honours Robert (Bob) Owen Meyer (b. 1956) of Maple Valley, Washington, USA. Mr Meyer acquired his first specimen from the Mammoth-Saint Anthony mine in 1978 and has subsequently spent thousands of hours studying specimens from the deposit.
Closely (structurally) related to cerchiaraite group and ashburtonite. Contains some Cr3+. Unique combination of elements.
In the structure there are (1) corner sharing SiO4 tetrahedra, forming Si4O12 rings centered on the c axis and alternating along [001] with Cl atoms; (2) chains of edge-sharing AlO6 octahedra, parallel to [001], that provide a link for the rings; (3) large channels || [001]; (4) two non-equivalent PbO10Cl polyhedra, with 8 framework and 2 channel oxygens, and off-centered Pb atoms; (5) channel-hosted water molecules loosely bond to Pb; (6) excess S, Cr3+, and Si (0.58, 0.40 and 0.13 apfu, respectively), presumably tetrahedrally coordinated within channels.
In the structure there are (1) corner sharing SiO4 tetrahedra, forming Si4O12 rings centered on the c axis and alternating along [001] with Cl atoms; (2) chains of edge-sharing AlO6 octahedra, parallel to [001], that provide a link for the rings; (3) large channels || [001]; (4) two non-equivalent PbO10Cl polyhedra, with 8 framework and 2 channel oxygens, and off-centered Pb atoms; (5) channel-hosted water molecules loosely bond to Pb; (6) excess S, Cr3+, and Si (0.58, 0.40 and 0.13 apfu, respectively), presumably tetrahedrally coordinated within channels.
Unique Identifiers
Mindat ID:
43334
Long-form identifier:
mindat:1:1:43334:7
IMA Classification of Bobmeyerite
Classification of Bobmeyerite
9.CF.
9 : SILICATES (Germanates)
C : Cyclosilicates
F : [Si4O12]8- 4-membered single rings, with insular complex anions
9 : SILICATES (Germanates)
C : Cyclosilicates
F : [Si4O12]8- 4-membered single rings, with insular complex anions
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 |
|---|---|---|
| Bmy | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Pronunciation of Bobmeyerite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Bobmeyerite
Vitreous
Transparency:
Transparent, Translucent
Colour:
Colorless to white
Streak:
White
Comment:
could not be measured
Tenacity:
Brittle
Cleavage:
None Observed
Comment:
frature could not be determined
Density:
4.381 g/cm3 (Calculated)
Optical Data of Bobmeyerite
Type:
Biaxial (-)
RI values:
nα = 1.756(4) nβ = 1.759(2) nγ = 1.759(2)
2V:
Measured: not determined° , Calculated: not determined°
Max. Birefringence:
δ = 0.003
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
Pleochroism:
Non-pleochroic
Comments:
The small size of the fibres precluded conoscopic observation, and therefore the 2V could not be determined, but it is expected to be very small.
Chemistry of Bobmeyerite
Mindat Formula:
Pb4(Al3Cu)(Si4O12)(S0.5Si0.5O4)(OH)7Cl(H2O)3
The above formula is from the original description; the formula from the IMA proposal: Pb4Al4(Si4O12)(OH)11Cl(H2O)
The above formula is from the original description; the formula from the IMA proposal: Pb4Al4(Si4O12)(OH)11Cl(H2O)
Element Weights:
Common Impurities:
F,Cr,(Ca)
Crystallography of Bobmeyerite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pnnm
Setting:
Pnnm
Cell Parameters:
a = 13.969(9) Å, b = 14.243(10) Å, c = 5.893(4) Å
Ratio:
a:b:c = 0.981 : 1 : 0.414
Unit Cell V:
1173.6 ų
Z:
2
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) |
|---|---|---|---|---|---|---|---|
| 0019796 | Bobmeyerite | Kampf A R, Pluth J J, Chen Y S, Roberts A C, Housley R M (2013) Bobmeyerite, a new mineral from Tiger, Arizona, USA, structurally related to cerchiaraite and ashburtonite Mineralogical Magazine 77 81-91 | 2013 | Tiger mine, Arizona, USA | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 10.051 Å | (35) |
| 5.474 Å | (54) |
| 5.011 Å | (35) |
| 4.333 Å | (43) |
| 3.278 Å | (77) |
| 2.966 Å | (88) |
| 2.549 Å | (100) |
| 1.873 Å | (39) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) |
Type Occurrence of Bobmeyerite
General Appearance of Type Material:
needles which are elongated on [001] and taper to sharp points
Place of Conservation of Type Material:
Mineral Sciences Department, Natural
History Museum of Los Angeles County, Los Angeles, California, USA, catalogue numbers 63824, 63825 and 63826
History Museum of Los Angeles County, Los Angeles, California, USA, catalogue numbers 63824, 63825 and 63826
Geological Setting of Type Material:
baryte, fluorite and ores of gold, lead, molybdenum, silver, tungsten, vanadium and zinc deposit with oxidation attributed to progressive alteration and crystallization in a closed system.
Associated Minerals at Type Locality:
Synonyms of Bobmeyerite
Other Language Names for Bobmeyerite
Dutch:Bobmeyeriet
German:Bobmeyerit
Common Associates
Associations Based on Photo Data:
| 8 photos of Bobmeyerite associated with Cerussite | PbCO3 |
| 6 photos of Bobmeyerite associated with Quartz | SiO2 |
| 5 photos of Bobmeyerite associated with Caledonite | Pb5Cu2(SO4)3(CO3)(OH)6 |
| 4 photos of Bobmeyerite associated with Georgerobinsonite | Pb4(CrO4)2(OH)2FCl |
| 3 photos of Bobmeyerite associated with Diaboleite | Pb2CuCl2(OH)4 |
| 1 photo of Bobmeyerite associated with Leadhillite | Pb4(CO3)2(SO4)(OH)2 |
Related Minerals - Strunz-mindat Grouping
| 9.CF.05 | Ashburtonite | Pb4Cu4(Si4O12)(HCO3)4(OH)3Cl · H2O |
| 9.CF.10 | Kainosite-(Y) | Ca2Y2(SiO3)4(CO3) · H2O |
| 9.CF.15 | Clinophosinaite | Na12(Ca,Sr)4(Si4O12)(PO4)4 |
| 9.CF.15 | Phosinaite-(Ce) | Na13Ca2(Ce,La,Th,Nd,Pr)(Si4O12)(PO4)4 |
| 9.CF.20 | Strakhovite | NaBa3Mn2+2Mn3+2Si6O19(OH)3 |
| 9.CF.25 | Cerchiaraite-(Al) | Ba4Al4O3(OH)3(Si4O12)[Si2O3(OH)4]Cl |
| 9.CF.25 | Cerchiaraite-(Fe) | Ba4Fe3+4O3(OH)3(Si4O12)[Si2O3(OH)4]Cl |
| 9.CF.25 | Cerchiaraite-(Mn) | Ba4Mn3+4(Si4O12)O2(OH)4Cl2[Si2O3(OH)4] |
Other Information
IR Spectrum:
OH & H2O: 3386 cm-1 (stretching), 1649 cm-1 (bending)
Notes:
Bobmeyerite dissolves very slowly in concentrated HCl; it is insoluble and unreactive in concentrated H2SO4 and 70% HNO3.
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 Bobmeyerite
mindat.org URL:
https://www.mindat.org/min-43334.html
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References for Bobmeyerite
Reference List:
Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2012) New minerals and nomenclature modifications approved in 2012. CNMNC Newsletter No 14. Mineralogical Magazine, 76 (5) 1281-1288 doi:10.1180/minmag.2012.076.5.15
Localities for Bobmeyerite
Showing 1 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.
USA (TL) | |
| Williams et al. (2012) +1 other reference |
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Mammoth-Saint Anthony Mine, St. Anthony deposit, Tiger, Mammoth Mining District, Pinal County, Arizona, USA