Millsite
A valid IMA mineral species
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About Millsite
Formula:
Cu2+(Te4+O3) · 2H2O
Colour:
Cyan to royal blue
Lustre:
Vitreous
Crystal System:
Monoclinic
Name:
Named in honour of Dr Stuart Mills (b.1982), mineralogist, crystallographer and Senior Curator of Geosciences, Museum Victoria, Australia, who has described numerous new minerals and who worked on nomenclature and crystallographic questions. Dr Mills is also (currently - 2016) Secretary of the IMA Commission on New Minerals, Nomenclature and Classification.
The mineral was first found by the Norwegian collector Kjell Arve Isbrekken in 1991 in a loose boulder at Gråurdfjellet, Oppdal, Sør-Trøndelag, Norway.
The mineral was first found by the Norwegian collector Kjell Arve Isbrekken in 1991 in a loose boulder at Gråurdfjellet, Oppdal, Sør-Trøndelag, Norway.
Type Locality:
Dimorph of:
A polymorph of teineite.
At the type locality millsite occurs together with teineite, which here has generally a more darker royal blue color. This feature has been used by collectors to distinguish between the two phases. But using the color is not an infallible way to distinguish between them (Rumsey et al. 2018).
At the type locality millsite occurs together with teineite, which here has generally a more darker royal blue color. This feature has been used by collectors to distinguish between the two phases. But using the color is not an infallible way to distinguish between them (Rumsey et al. 2018).
Unique Identifiers
Mindat ID:
46965
Long-form identifier:
mindat:1:1:46965:2
GUID
(UUID V4):
(UUID V4):
93f88b59-2363-47c9-b4af-74760f8a9687
IMA Classification of Millsite
Approved
IMA Formula:
CuTeO3 · 2H2O
Approval year:
2015
First published:
2018
Classification of Millsite
4.JM.25
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
J : Arsenites, antimonites, bismuthites, sulfites, selenites, tellurites; iodates
M : Tellurites without additional anions, with H2O
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
J : Arsenites, antimonites, bismuthites, sulfites, selenites, tellurites; iodates
M : Tellurites without additional anions, with H2O
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 |
---|---|---|
Mls | 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 Millsite
Vitreous
Transparency:
Transparent
Colour:
Cyan to royal blue
Streak:
Pale green
Tenacity:
Brittle
Cleavage:
Perfect
Perfect (100). Broken fragments appear platy on (100).
Perfect (100). Broken fragments appear platy on (100).
Fracture:
Conchoidal
Optical Data of Millsite
Type:
Biaxial (+)
RI values:
nα = 1.756(5) nβ = 1.794(5) nγ = 1.925
2V:
Measured: 60° (1)
Max Birefringence:
δ = 0.169
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:
Very High
Chemistry of Millsite
Mindat Formula:
Cu2+(Te4+O3) · 2H2O
Elements listed:
Crystallography of Millsite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Setting:
P21/c
Cell Parameters:
a = 7.4049(2) Å, b = 7.7873(2) Å, c = 8.5217(2) Å
β = 110.203(3)°
β = 110.203(3)°
Ratio:
a:b:c = 0.951 : 1 : 1.094
Unit Cell V:
461.17 ų
Z:
4
X-Ray Powder Diffraction
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
6.954 Å | (100) |
3.558 Å | (64) |
3.175 Å | (39) |
2.838 Å | (47) |
2.675 Å | (43) |
Comments:
From type description
Geological Environment
Paragenetic Mode(s):
Paragenetic Mode | Earliest Age (Ga) |
---|---|
Stage 7: Great Oxidation Event | <2.4 |
47a : [Near-surface hydration of prior minerals] |
Type Occurrence of Millsite
Place of Conservation of Type Material:
Cotype material is deposited in the mineralogical collections of the Natural History Museum, London, UK, registration number BM 2011,243, the Natural History Museum of Los Angeles County, Los Angeles, California, USA, catalogue number 66264, and the Museum Victoria, Melbourne, Australia, Catalogue number M53498.
Empirical Formula of Type Material:
Cu0.99(Te0.98Se0.02)O3(H2O)2
Chemical Analysis of Type Material:
CuO | 30.14 % |
---|---|
SeO2 | 0.78 % |
TeO2 | 60.25 % |
H2O calc | 13.79 % |
Total: | 104.96 % |
Associated Minerals at Type Locality:
Reference:
Rumsey, M.S., Welch, M.D., Mo, F., Kleppe, A.K., Spratt, J., Kampf, A.R., Raanes, M.P. (2018) Millsite CuTeO3·2H2O: a new polymorph of teineite from Gråurdfjellet, Oppdal kommune, Norway. Mineralogical Magazine: 82: 433-444.
Synonyms of Millsite
Common Associates
Associated Minerals Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
4.JM. | Rudolfhermannite | Fe(Te4+O3)3 · H2O |
4.JM. | Wortupaite | MgNi2+2(Te4+O3)3 · 3H2O |
4.JM.05 | Keystoneite | Mg0.5Ni2+Fe3+(Te4+O3)3 · 4.5H2O |
4.JM.05 | Kinichilite | Mg0.5Mn2+Fe3+(Te4+O3)3 · 4.5H2O |
4.JM.05 | Zemannite | Mg0.5ZnFe3+(Te4+O3)3 · 4.5H2O |
4.JM.05 | Ilirneyite | Mg0.5ZnMn3+(Te4+O3)3 · 4.5H2O |
4.JM.10 | Blakeite | Fe3+2[TeO3]3 (?) |
4.JM.10 | Emmonsite | Fe3+2(TeO3)3 · 2H2O |
4.JM.15 | Graemite | Cu[TeO3] · H2O |
4.JM.20 | Teineite | Cu2+(Te4+O3) · 2H2O |
4.JM.20 | Telluromandarinoite | Fe3+2Te3O9 · 6H2O |
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 Millsite
mindat.org URL:
https://www.mindat.org/min-46965.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Millsite
Reference List:
www.nhm.org (2012) http://www.nhm.org/site/research-collections/mineral-sciences/research-studies/anthony-r-kampf
Localities for Millsite
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).
Struck out - Mineral was erroneously reported from this locality.
Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).
All localities listed without proper references should be considered as questionable.
All localities listed without proper references should be considered as questionable.
Norway (TL) | |
| Mineralogical Magazine +2 other references |
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Millsite boulder, Gråurdfjellet, Oppdal, Trøndelag, Norway