Gerdtremmelite
A valid IMA mineral species
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About Gerdtremmelite
Gerd Tremmel in Tsumeb
Formula:
(Zn,Fe)(Al,Fe)2(AsO4)(OH)5
Colour:
Yellowish brown to dark brown
Lustre:
Adamantine
Specific Gravity:
3.66 (Calculated)
Crystal System:
Triclinic
Name:
Named after Dr. Gerd Tremmel (1940-12-02-2020), of Overath-Steinbrück, Germany, collector and specialist for minerals from Tsumeb, who submitted the type material for identification.
This page provides mineralogical data about Gerdtremmelite.
Unique Identifiers
Mindat ID:
1679
Long-form identifier:
mindat:1:1:1679:3
IMA Classification of Gerdtremmelite
Approved
IMA Formula:
Zn2+Al2As5+O4(OH)5
Approval year:
1983
First published:
1985
Classification of Gerdtremmelite
8.BE.40
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
E : With only medium-sized cations, (OH, etc.):RO4 > 2:1
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
E : With only medium-sized cations, (OH, etc.):RO4 > 2:1
41.3.7.1
41 : ANHYDROUS PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
3 : (AB)3(XO4)Zq
41 : ANHYDROUS PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
3 : (AB)3(XO4)Zq
20.4.10
20 : Arsenates (also arsenates with phosphate, but without other anions)
4 : Arsenates of Group III metals (Al, rare earths)
20 : Arsenates (also arsenates with phosphate, but without other anions)
4 : Arsenates of Group III metals (Al, rare earths)
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 |
|---|---|---|
| Gtm | 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 Gerdtremmelite
Adamantine
Transparency:
Transparent
Colour:
Yellowish brown to dark brown
Streak:
White
Cleavage:
None Observed
Fracture:
None observed
Density:
3.66 g/cm3 (Calculated)
Optical Data of Gerdtremmelite
Type:
Biaxial
RI values:
nα = 1.73 - 1.74 nγ = 1.83 - 1.84
Max. Birefringence:
δ = 0.100
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:
Very High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Dispersion:
r > v
Chemistry of Gerdtremmelite
Mindat Formula:
(Zn,Fe)(Al,Fe)2(AsO4)(OH)5
Element Weights:
Crystallography of Gerdtremmelite
Crystal System:
Triclinic
Cell Parameters:
a = 5.169(5) Å, b = 13.038(9) Å, c = 4.931(4) Å
α = 98.78°, β = 100.80(6)°, γ = 78.73°
α = 98.78°, β = 100.80(6)°, γ = 78.73°
Ratio:
a:b:c = 0.396 : 1 : 0.378
Unit Cell V:
317.81 ų (Calculated from Unit Cell)
Z:
2
Comment:
Point Group: 1 or 1.; Space Group: P1 or P1.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 12.77 Å | (100) |
| 3.878 Å | (50) |
| 3.631 Å | (50) |
| 3.140 Å | (50) |
| 4.801 Å | (40) |
| 4.695 Å | (40) |
| 4.220 Å | (40) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47d : [Arsenates, antimonates, selenates, bismuthinates] |
Type Occurrence of Gerdtremmelite
Place of Conservation of Type Material:
Mineralogical-Petrographical Institute, University of Heidelberg, Heidelberg, Germany; National Museum of Natural History, Washington, D.C., USA, 162488.
Associated Minerals at Type Locality:
Synonyms of Gerdtremmelite
Other Language Names for Gerdtremmelite
Common Associates
Associations Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
| 8.BE.05 | Augelite | Al2(PO4)(OH)3 |
| 8.BE.10 | Grattarolaite | Fe3+3(PO4)O3 |
| 8.BE.15 | Cornetite | Cu3(PO4)(OH)3 |
| 8.BE.20 | Clinoclase | Cu3(AsO4)(OH)3 |
| 8.BE.25 | Gilmarite | Cu3(AsO4)(OH)3 |
| 8.BE.25 | Arhbarite | Cu2Mg(AsO4)(OH)3 |
| 8.BE.30 | Flinkite | Mn2+2Mn3+(AsO4)(OH)4 |
| 8.BE.30 | Argandite | Mn7(VO4)2(OH)8 |
| 8.BE.30 | Raadeite | Mg7(PO4)2(OH)8 |
| 8.BE.30 | Allactite | Mn2+7(AsO4)2(OH)8 |
| 8.BE.35 | 'Mineral E (of Dunn, et. al., 1982)' | |
| 8.BE.35 | Chlorophoenicite | (Mn,Mg)3Zn2(AsO4)(OH,O)6 |
| 8.BE.35 | Magnesiochlorophoenicite | (Mg,Mn)3Zn2(AsO4)(OH,O)6 |
| 8.BE.45 | Dixenite | CuMn2+14Fe2+(SiO4)2(As5+O4)(As3+O3)5(OH)6 |
| 8.BE.45 | Mcgovernite | Mn19Zn3(AsO4)3(AsO3)(SiO4)3(OH)21 |
| 8.BE.45 | Hematolite | (Mn,Mg,Al,Fe3+)15(As5+O4)2(As3+O3)(OH)23 |
| 8.BE.45 | Turtmannite | (Mn,Mg)22.5Mg3-3x((V5+,As5+)O4)3(As3+O3)x(SiO4)3O5-5x(OH)20+x |
| 8.BE.45 | Carlfrancisite | Mn2+3(Mn2+,Mg,Fe3+,Al)42[As3+O3]2(As5+O4)4[(Si,As5+)O4]6[(As5+,Si)O4]2(OH)42 |
| 8.BE.45 | Arakiite | (Zn,Mn2+)(Mn2+,Mg)12(Fe3+,Al)2(As5+O4)2(As3+O3)(OH)23 |
| 8.BE.45 | Kraisslite | Zn3(Mn,Mg)25(Fe3+,Al)(As3+O3)2[(Si,As5+)O4]10(OH)16 |
| 8.BE.50 | Synadelphite | Mn2+9(As5+O4)2(As3+O3)(OH)9 · 2H2O |
| 8.BE.55 | Holdenite | (Mn2+,Mg)6Zn3(AsO4)2(SiO4)(OH)8 |
| 8.BE.60 | Kolicite | Mn2+7Zn4(AsO4)2(SiO4)2(OH)8 |
| 8.BE.65 | Sabelliite | (Cu,Zn)2Zn(AsO4,SbO4)(OH)3 |
| 8.BE.70 | Jarosewichite | Mn2+3Mn3+(AsO4)(OH)6 |
| 8.BE.75 | Theisite | Cu5Zn5(AsO4,SbO4)2(OH)14 |
| 8.BE.80 | Coparsite | Cu4(AsO4,VO4)O2Cl |
| 8.BE.85 | Waterhouseite | Mn2+7(PO4)2(OH)8 |
| 8.BE.90 | Vasilseverginite | Cu9O4(AsO4)2(SO4)2 |
Fluorescence of Gerdtremmelite
None observed
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 Gerdtremmelite
mindat.org URL:
https://www.mindat.org/min-1679.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
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References for Gerdtremmelite
Reference List:
Localities for Gerdtremmelite
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.
Namibia (TL) | |
| Schmetzer et al. (1985) +1 other reference |
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Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia