Oxycalciomicrolite
A valid IMA mineral species
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About Oxycalciomicrolite
Formula:
Ca2Ta2O6O
Also given as Ca2Ta2O7.
Colour:
Brownish-yellow to brownish-red
Lustre:
Vitreous, Resinous
Hardness:
5 - 5½
Specific Gravity:
6.333 (Calculated)
Crystal System:
Isometric
Member of:
Name:
Named for being the oxygen- and calcium-dominant member of the microlite group.
Type Locality:
The Ca- and oxide-dominant member of the group. Approved in 2020.
Analyses published (Christy & Atencio, 2013).
Analyses published (Christy & Atencio, 2013).
Unique Identifiers
Mindat ID:
40355
Long-form identifier:
mindat:1:1:40355:9
GUID
(UUID V4):
(UUID V4):
0cde9efa-61d1-4962-8b31-c39ba08e3477
Classification of Oxycalciomicrolite
Approved
First published:
2020
4.DH.15
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar
H : With large (+- medium-sized) cations; sheets of edge-sharing octahedra
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar
H : With large (+- medium-sized) cations; sheets of edge-sharing octahedra
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 |
|---|---|---|
| Ocmic | 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 Oxycalciomicrolite
Vitreous, Resinous
Transparency:
Translucent
Colour:
Brownish-yellow to brownish-red
Streak:
White
Hardness:
5 - 5½ on Mohs scale
Tenacity:
Brittle
Cleavage:
None Observed
Parting:
None observed
Density:
6.333 g/cm3 (Calculated)
Optical Data of Oxycalciomicrolite
Type:
Isotropic
RI values:
n = 2.037
Birefringence:
Isotropic minerals have no birefringence
Surface Relief:
Very High
Chemical Properties of Oxycalciomicrolite
Formula:
Ca2Ta2O6O
Also given as Ca2Ta2O7.
Also given as Ca2Ta2O7.
IMA Formula:
Ca2Ta2O7
Elements listed:
Crystallography of Oxycalciomicrolite
Crystal System:
Isometric
Class (H-M):
m3m (4/m 3 2/m) - Hexoctahedral
Space Group:
Fd3m
Setting:
Fd3m
Cell Parameters:
a = 10.4325(4) Å
Unit Cell V:
1135.46 ų
Z:
8
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 6.023 Å | (89) |
| 3.145 Å | (44) |
| 3.011 Å | (100) |
| 2.608 Å | (25) |
| 2.008 Å | (14) |
| 1.844 Å | (48) |
| 1.763 Å | (11) |
| 1.573 Å | (33) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 34 : Complex granite pegmatites |
Type Occurrence of Oxycalciomicrolite
General Appearance of Type Material:
Octahedral crystals, ranging from 0.2 to 0.5 mm in size.
Place of Conservation of Type Material:
Mineralogical collections of the Museu Nacional, Universidade Federal do Rio de Janeiro, Quinta da Boa Vista s/n, 20940-040 Rio de Janeiro, Brazil, registration number MN-7601-M
Geological Setting of Type Material:
Pegmatite
Associated Minerals at Type Locality:
Reference:
Menezes da Silva, V.H.R., Ávila, C.A., Neumann, R., Leite Faulstich, F.R., Alves, F.E.A., Barra de Almeida, F., Proença Cidade, T., da Cruz Guimarães Sousa, S.S. (2020): Oxycalciomicrolite, (Ca,Na)2(Ta,Nb,Ti)2O6(O,F), a new member of the microlite group (pyrochlore supergroup) from the Paleoproterozoic São João del Rei Pegmatite Province, Minas Gerais state, Brazil. Mineralogical Magazine: 84(6): 854-858.
Synonyms of Oxycalciomicrolite
Calciomicrolite (in part)
Relationship of Oxycalciomicrolite to other Species
Member of:
Other Members of this group:
| Fluorcalciomicrolite | (Ca,Na)2(Ta,Nb)2O6F | Iso. m3m (4/m 3 2/m) : Fd3m |
| Fluornatromicrolite | (Na1.5Bi0.5)Ta2O6F | Iso. m3m (4/m 3 2/m) : Fd3m |
| Hydrokenomicrolite | (◻,H2O)2Ta2(O,OH)6(H2O) | Iso. m3m (4/m 3 2/m) |
| Hydromicrolite | (H2O,◻)2Ta2(O,OH)6(H2O) | |
| Hydroxycalciomicrolite | Ca1.5Ta2O6(OH) | Iso. 4 3 2 : P42 3 2 |
| Hydroxykenomicrolite | (◻,Na,Sb3+)2Ta2O6(OH) | Iso. m3m (4/m 3 2/m) : Fd3m |
| Hydroxynatromicrolite | (Na,Bi3+,◻)2Ta2O6(OH) | Iso. m3m (4/m 3 2/m) : Fd3m |
| Kenoplumbomicrolite | (Pb,◻)2Ta2O6(◻,OH,O) | Iso. |
| Oxybismutomicrolite | (Bi1.33◻0.67)Σ2Ta2O6O | Iso. m3m (4/m 3 2/m) : Fd3m |
| Oxystannomicrolite | Sn2Ta2O6O | Iso. m3m (4/m 3 2/m) : Fd3m |
| Oxystibiomicrolite | (Sb3+,Ca)2Ta2O6O | Iso. m3m (4/m 3 2/m) : Fd3m |
| Uranmicrolite (of Hogarth 1977) | (Ca,U,Na)2-x(Ta,Nb)2(O,OH)7 | Iso. |
| Yttromicrolite (of Hogarth) | (Ca,Y3+,U,Na)2-x(Ta,Nb,Ti,Fe3+)2O7 | Iso. m3m (4/m 3 2/m) : Fd3m |
Related Minerals - Strunz-mindat Grouping
| 4.DH. | Fluornatropyrochlore | (Na,Pb,Ca,REE,U)2Nb2O6F |
| 4.DH. | Roméite Group | A2(Sb5+)2O6Z |
| 4.DH. | Hydroxykenomicrolite | (◻,Na,Sb3+)2Ta2O6(OH) |
| 4.DH. | Fluornatroroméite | (Na,Ca)2Sb2(O,OH)6F |
| 4.DH. | Oxyplumboroméite | Pb2Sb2O6O |
| 4.DH. | Cesiokenopyrochlore | ◻Nb2(O,OH)6(Cs,◻) |
| 4.DH. | Oxyyttrobetafite-(Y) | Y2Ti2O6O |
| 4.DH.05 | Brannerite | UTi2O6 |
| 4.DH.05 | Orthobrannerite | U4+U6+Ti4O12(OH)2 |
| 4.DH.05 | Thorutite | (Th,U,Ca)Ti2(O,OH)6 |
| 4.DH.10 | Kassite | CaTi2O4(OH)2 |
| 4.DH.10 | Lucasite-(Ce) | CeTi2(O,OH)6 |
| 4.DH.15 va | Alumotungstite | ◻2W2O6(H2O) |
| 4.DH.15 | Bismutomicrolite (of Hogarth 1977) | |
| 4.DH.15 | Hydroplumboelsmoreite | (Pb,◻)(W,Fe3+)2O6 · H2O |
| 4.DH.15 | Hydropyrochlore | (H2O,◻)2Nb2(O,OH)6(H2O) |
| 4.DH.15 | Plumbomicrolite (of Hogarth 1977) | |
| 4.DH.15 | Stibiomicrolite (of Groat et al.) | |
| 4.DH.15 | Strontiopyrochlore (of Hogarth 1977) | A2Nb2(O,OH)6Z |
| 4.DH.15 | Fluornatromicrolite | (Na1.5Bi0.5)Ta2O6F |
| 4.DH.15 | Bismutopyrochlore (of Chukanov et al.) | (Bi,Ca,U,Pb)2-xNb2(O,OH)6(OH) |
| 4.DH.15 | Hydrokenoelsmoreite | ◻2W2O6(H2O) |
| 4.DH.15 | Fluorcalciomicrolite | (Ca,Na)2(Ta,Nb)2O6F |
| 4.DH.15 | Oxycalciobetafite | Ca2(Ti,Nb)2O6O |
| 4.DH.15 va | Yttromicrolite (of Hogarth) | (Ca,Y3+,U,Na)2-x(Ta,Nb,Ti,Fe3+)2O7 |
| 4.DH.15 | Oxynatropyrochlore | (Na,Ca,U)2Nb2O6(O,OH) |
| 4.DH.15 | Hydroxycalciopyrochlore | (Ca,Na,U,◻)2(Nb,Ti)2O6(OH) |
| 4.DH.15 | Fluorcalciopyrochlore | (Ca,Na)2(Nb, Ti)2O6F |
| 4.DH.15 | Oxycalciopyrochlore | Ca2Nb2O6O |
| 4.DH.15 | Fluorstrontiopyrochlore | (Sr,◻)2Nb2(O,OH)6F |
| 4.DH.15 | Oxyplumbopyrochlore | Pb2Nb2O6O |
| 4.DH.15 | Kenoplumbopyrochlore | (Pb,◻)Nb2O6(◻,O) |
| 4.DH.15 | Oxyyttropyrochlore-(Y) | (Y,◻)2Nb2O6O |
| 4.DH.15 | Fluorkenopyrochlore | (◻,Sr,Ce,Ca,Na)2(Nb,Ti)2O6F |
| 4.DH.15 | Oxyuranobetafite | (U,Ca,◻)2(Ti,Nb)2O6O |
| 4.DH.15 | Oxystannomicrolite | Sn2Ta2O6O |
| 4.DH.15 | Kenoplumbomicrolite | (Pb,◻)2Ta2O6(◻,OH,O) |
| 4.DH.15 | Oxystibiomicrolite | (Sb3+,Ca)2Ta2O6O |
| 4.DH.15 | Hydromicrolite | (H2O,◻)2Ta2(O,OH)6(H2O) |
| 4.DH.15 | Hydrokenomicrolite | (◻,H2O)2Ta2(O,OH)6(H2O) |
| 4.DH.15 | Hydroxymanganopyrochlore | (Mn2+,Th,Na,Ca,REE)2(Nb,Ti)2O6(OH) |
| 4.DH.15 | Hydroxycalciomicrolite | Ca1.5Ta2O6(OH) |
| 4.DH.15 | Fluorplumbopyrochlore | (Pb,Y,Th,U,Na,Ca)2-x(Nb,Ti)2O6F |
| 4.DH.15 | Hydroxyplumbopyrochlore | (Pb1.5◻0.5)Nb2O6(OH) |
| 4.DH.15 | Oxynatromicrolite | (Na,Ca,U)2(Ta,Nb)2O6(O,F) |
| 4.DH.15 | Fluorhydropyrochlore | |
| 4.DH.15 | Hydroxykenoelsmoreite | (◻,Pb)2(W,Fe3+,Al)2(O,OH)6(OH) |
| 4.DH.15 | Hydrokenopyrochlore | (◻,x)2Nb2O6(H2O,Cs) |
| 4.DH.15 | Hydroxykenopyrochlore | (◻,Ce,Ba)2(Nb,Ti)2O6(OH,F) |
| 4.DH.15 | Hydroxynatropyrochlore | (Na,Ca,Ce)2Nb2O6(OH) |
| 4.DH.15 | Hydroxynatromicrolite | (Na,Bi3+,◻)2Ta2O6(OH) |
| 4.DH.15 | Unnamed (Sb-analogue of Hydroxymanganopyrochlor) | (Mn,Ca,Y)2(Sb,Ti)2O6(OH) |
| 4.DH.15 | Oxybismutomicrolite | (Bi1.33◻0.67)Σ2Ta2O6O |
| 4.DH.20 | Bindheimite | Pb2Sb2O6O |
| 4.DH.20 | Hydroxycalcioroméite | (Ca,Sb3+)2(Sb5+,Ti)2O6(OH) |
| 4.DH.20 | Monimolite | Pb2Sb5+2O7 |
| 4.DH.20 | Cuproroméite | Cu2Sb2(O,OH)7 |
| 4.DH.20 | Stetefeldtite | Ag2Sb2(O,OH)7 |
| 4.DH.20 | Stibiconite | Sb3+Sb5+2O6(OH) |
| 4.DH.20 | Fluorcalcioroméite | (Ca,Na,◻)2Sb5+2(O,OH)6F |
| 4.DH.20 | Oxycalcioroméite | Ca2Sb2O6O |
| 4.DH.20 | Hydroxyferroroméite | (Fe2+1.5◻0.5)Sb5+2O6(OH) |
| 4.DH.25 | Rosiaite | PbSb5+2O6 |
| 4.DH.30 | Zirconolite | CaZrTi2O7 |
| 4.DH.30 | Laachite | (Ca,Mn)2Zr2Nb2TiFeO14 |
| 4.DH.30 | Nöggerathite-(Ce) | (Ce,Ca)2Zr2(Nb,Ti)(Ti,Nb)2Fe2+O14 |
| 4.DH.30 | Stefanweissite | (Ca,REE)2Zr2(Nb,Ti)(Ti,Nb)2Fe2+O14 |
| 4.DH.35 | Liandratite | U(Nb,Ta)2O8 |
| 4.DH.35 | Petscheckite | UFe(Nb,Ta)2O8 |
| 4.DH.40 | Ingersonite | Ca3Mn2+Sb5+4O14 |
| 4.DH.45 | Pittongite | Na0.22(W,Fe3+)(O,OH)3 · 0.44H2O |
| 4.DH.50 | Tazzoliite | Ba4-xNaxTi2Nb3SiO17[PO2(OH)2]x(OH)(1-2x) |
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 Oxycalciomicrolite
mindat.org URL:
https://www.mindat.org/min-40355.html
Please feel free to link to this page.
Please feel free to link to this page.
External Links:
Mineral Dealers:
References for Oxycalciomicrolite
Reference List:
Localities for Oxycalciomicrolite
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.
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Ipê mine, Governador Valadares, Minas Gerais, Brazil