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Olmiite

A valid IMA mineral species

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Photos of Olmiite (472)

Olmiite Gallery Search Photos of Olmiite

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Olmiite

N'Chwaning II Mine, N'Chwaning Mines, Joe Morolong Local Municipality, John Taolo Gaetsewe District Municipality, Northern Cape, South Africa

Olmiite

N'Chwaning II Mine, N'Chwaning Mines, Joe Morolong Local Municipality, John Taolo Gaetsewe District Municipality, Northern Cape, South Africa

Olmiite, etc.

N'Chwaning II Mine, N'Chwaning Mines, Joe Morolong Local Municipality, John Taolo Gaetsewe District Municipality, Northern Cape, South Africa

Olmiite

N'Chwaning II Mine, N'Chwaning Mines, Joe Morolong Local Municipality, John Taolo Gaetsewe District Municipality, Northern Cape, South Africa

Olmiite

N'Chwaning II Mine, N'Chwaning Mines, Joe Morolong Local Municipality, John Taolo Gaetsewe District Municipality, Northern Cape, South Africa

Olmiite, etc.

N'Chwaning II Mine, N'Chwaning Mines, Joe Morolong Local Municipality, John Taolo Gaetsewe District Municipality, Northern Cape, South Africa

Olmiite

N'Chwaning II Mine, N'Chwaning Mines, Joe Morolong Local Municipality, John Taolo Gaetsewe District Municipality, Northern Cape, South Africa

Olmiite

N'Chwaning II Mine, N'Chwaning Mines, Joe Morolong Local Municipality, John Taolo Gaetsewe District Municipality, Northern Cape, South Africa

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About OlmiiteHide

Formula:

CaMn²⁺[SiO₃(OH)](OH)

Colour:

Pale to intense reddish pink.

Lustre:

Vitreous

Hardness:

5 - 5½

Specific Gravity:

3.05

Crystal System:

Orthorhombic

Name:

Named for Filippo Olmi (1959-2005) who worked at CNR, Centro di Studio per la Minerogenesi e Geochimica Applicata, Florence, Italy.

Type Locality:

ⓘ N'Chwaning II Mine, N'Chwaning Mines, Joe Morolong Local Municipality, John Taolo Gaetsewe District Municipality, Northern Cape, South Africa

Mn²⁺-dominant analogue of Poldervaartite.

A product of hydrothermal alteration.

Note: Most (all?) "poldervaartites" seem to be olmiites, see http://www.mindat.org/mesg-7-104499.html.

Unique IdentifiersHide

Mindat ID:

30762

Long-form identifier:

mindat:1:1:30762:6

GUID
(UUID V4):

e64b86c2-3ef8-43f1-80e3-e01d0f90c0d0

IMA Classification of OlmiiteHide

IMA status:

Approved

IMA Formula:

CaMn[SiO₃(OH)](OH)

Approval year:

2006

First published:

2007

Type description reference:

Bonazzi, P., Bindi, L., Medenbach, O., Pagano, R., Lampronti, Menchetti, S. (2007): Olmiite, CaMn[SiO3(OH)](OH), the Mn-dominant analogue of poldervaartite, a new mineral species from Kalahari manganese fields (Republic of South Africa). Mineralogical Magazine: 71: 193-291.

Classification of OlmiiteHide

Strunz-mindat (2024):

9.AF.90

9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Symbol	Source	Reference
Olm	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 OlmiiteHide

Pronunciation:

Play	Recorded by	Country
	Jolyon Ralph	United Kingdom

Physical Properties of OlmiiteHide

Lustre:

Vitreous

Transparency:

Transparent

Colour:

Pale to intense reddish pink.

Streak:

White

Hardness:

5 - 5½ on Mohs scale

Tenacity:

Brittle

Cleavage:

None Observed

Fracture:

Irregular/Uneven

Density:

3.05 g/cm³ (Measured) 3.102 g/cm³ (Calculated)

Comment:

Calculated value based on unit cell volume; a value of 3.109 from powder data.

Optical Data of OlmiiteHide

Type:

Biaxial (+)

RI values:

n_α = 1.663(1) n_β = 1.672(1) n_γ = 1.694(1)

2V:

Measured: 71° , Calculated: 66°

Max Birefringence:

δ = 0.031

Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.

Surface Relief:

High

Dispersion:

r > v distinct

Pleochroism:

Non-pleochroic

Chemistry of OlmiiteHide

Mindat Formula:

CaMn²⁺[SiO₃(OH)](OH)

Elements listed:

Ca, H, Mn, O, Si - search for minerals with similar chemistry

Crystallography of OlmiiteHide

Crystal System:

Orthorhombic

Class (H-M):

mmm (2/m 2/m 2/m) - Dipyramidal

Space Group:

Pbca

Cell Parameters:

a = 9.249 Å, b = 9.076 Å, c = 10.342 Å

Ratio:

a:b:c = 1.019 : 1 : 1.139

Unit Cell V:

868 Å³

Morphology:

Crystals minute. Aggregates resemble wheat sheaves.

Crystal StructureHide

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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)
0014579	Olmiite	Bonazzi P, Bindi L, Medenbach O, Pagano R, Lampronti G I, Menchetti S (2007) Olmiite, CaMn[SiO3(OH)](OH), the Mn-dominant analogue of poldervaartite, a new mineral species from Kalahari manganese fields (Republic of South Africa) Mineralogical Magazine 71 193-201		2007	N'Chwaning II mine, Republic of South Africa	0	293

CIF Raw Data - click here to close

data_global
_chemical_name_mineral 'Olmiite'
loop_
_publ_author_name
'Bonazzi P'
'Bindi L'
'Medenbach O'
'Pagano R'
'Lampronti G I'
'Menchetti S'
_journal_name_full 'Mineralogical Magazine'
_journal_volume 71 
_journal_year 2007
_journal_page_first 193
_journal_page_last 201
_publ_section_title
;
 Olmiite, CaMn[SiO3(OH)](OH), the Mn-dominant analogue of poldervaartite,
 a new mineral species from Kalahari manganese fields (Republic of South Africa)
;
_database_code_amcsd 0014579
_chemical_compound_source 'N'Chwaning II mine, Republic of South Africa'
_chemical_formula_sum 'Ca1.14 Mn.84 Fe.01 Si O5 H2'
_cell_length_a 9.249
_cell_length_b 9.076
_cell_length_c 10.342
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 868.148
_exptl_crystal_density_diffrn      3.099
_symmetry_space_group_name_H-M 'P b c a'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  'x,1/2-y,1/2+z'
  '-x,1/2+y,1/2-z'
  '1/2-x,1/2+y,z'
  '1/2+x,1/2-y,-z'
  '1/2+x,y,1/2-z'
  '1/2-x,-y,1/2+z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
_atom_site_U_iso_or_equiv
Ca   0.15329   0.49245   0.39231   1.00000   0.00920
MnM2   0.50894   0.33741   0.43030   0.84000   0.01030
CaM2   0.50894   0.33741   0.43030   0.14000   0.01030
FeM2   0.50894   0.33741   0.43030   0.01000   0.01030
Si   0.32771   0.21852   0.65915   1.00000   0.00790
O2   0.94410   0.35440   0.43910   1.00000   0.01070
O3   0.10090   0.71440   0.28810   1.00000   0.01220
O4   0.40050   0.55090   0.40120   1.00000   0.01400
O5   0.19560   0.39530   0.18740   1.00000   0.01170
O1   0.25090   0.35680   0.57670   1.00000   0.01510
H1   0.24900   0.44100   0.61900   1.00000   0.04000
H2   0.43000   0.59500   0.33900   1.00000   0.04000
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
Ca 0.01000 0.00990 0.00770 -0.00030 0.00050 0.00020
MnM2 0.01180 0.01040 0.00860 -0.00230 -0.00060 -0.00010
CaM2 0.01180 0.01040 0.00860 -0.00230 -0.00060 -0.00010
FeM2 0.01180 0.01040 0.00860 -0.00230 -0.00060 -0.00010
Si 0.00960 0.00760 0.00650 -0.00010 -0.00010 -0.00020
O2 0.01010 0.01280 0.00940 -0.00140 -0.00180 -0.00170
O3 0.01640 0.01170 0.00860 0.00220 0.00370 0.00200
O4 0.01410 0.01520 0.01270 -0.00160 0.00060 0.00120
O5 0.01220 0.01290 0.00990 0.00230 0.00090 -0.00070
O1 0.02500 0.00760 0.01230 0.00270 -0.00670 -0.00030

X-Ray Powder DiffractionHide

Powder Diffraction Data:

d-spacing	Intensity
4.14 Å	(60)
4.10 Å	(30)
3.19 Å	(100)
2.807 Å	(35)
2.762 Å	(30)
2.545 Å	(35)
2.521 Å	(30)
2.361 Å	(40)

Geological EnvironmentHide

Paragenetic Mode(s):

Paragenetic Mode	Earliest Age (Ga)
Near-surface Processes
22 : Hydration and low-𝑇 subsurface aqueous alteration (see also #23)

Type Occurrence of OlmiiteHide

Type Locality:

ⓘ N'Chwaning II Mine, N'Chwaning Mines, Joe Morolong Local Municipality, John Taolo Gaetsewe District Municipality, Northern Cape, South Africa

General Appearance of Type Material:

Wheat sheaf aggregates.

Place of Conservation of Type Material:

Museo di Storia Naturale, Universita di Firenze, Italy, catalogue number 2987/I (holotype material).
Dipartimento di Scienze della Terra, Universita di Firenze, Italy.

Associated Minerals at Type Locality:

Reference:

Download:

https://rruff.info/rruff_1.0/uploads/MM71_193.pdf

Synonyms of OlmiiteHide

IMA2006-026

Olmiit

Relationship of Olmiite to other SpeciesHide

Forms a series with:

Poldervaartite

Olmiite-Poldervaartite Series

Common AssociatesHide

Associated Minerals Based on Photo Data:

193 photos of Olmiite associated with Calcite	CaCO₃
156 photos of Olmiite associated with Bultfonteinite	Ca₂(HSiO₄)F · H₂O
50 photos of Olmiite associated with Oyelite	Ca₁₀Si₈B₂O₂₉ · 12.5H₂O
19 photos of Olmiite associated with Quartz	SiO₂
19 photos of Olmiite associated with Xonotlite	Ca₆(Si₆O₁₇)(OH)₂
10 photos of Olmiite associated with Celestine	SrSO₄
6 photos of Olmiite associated with Hematite	Fe₂O₃
6 photos of Olmiite associated with Goethite	α-Fe³⁺O(OH)
6 photos of Olmiite associated with Poldervaartite	CaCa[SiO₃(OH)](OH)
5 photos of Olmiite associated with Manganite	Mn³⁺O(OH)

Related Minerals - Strunz-mindat Grouping Hide

9.AF.	Chegemite	Ca₇(SiO₄)₃(OH)₂	Orth. mmm (2/m 2/m 2/m)
9.AF.	Barwoodite	Mn²⁺₆Nb⁵⁺(SiO₄)₂O₃(OH)₃	Trig. 3 : P3
9.AF.	Jingwenite-(Y)	YAlV⁴⁺(SiO₄)O₂(OH)₂	Mon. 2/m
9.AF.05	Sillimanite	Al₂(SiO₄)O	Orth. mmm (2/m 2/m 2/m)
9.AF.05	Xenolite	Al₁₀Si₈O₃₁
9.AF.10	Andalusite	Al₂(SiO₄)O	Orth. mmm (2/m 2/m 2/m) : Pnnm
9.AF.10	Kanonaite	Mn³⁺Al(SiO₄)O	Orth. mmm (2/m 2/m 2/m) : Pnnm
9.AF.15	Kyanite	Al₂(SiO₄)O	Tric. 1 : P1
9.AF.20	Mullite	Al_4+2xSi_2-2xO_10-x	Orth. mmm (2/m 2/m 2/m) : Pbam
9.AF.20	Krieselite	Al₂(GeO₄)F₂	Orth. mmm (2/m 2/m 2/m) : Pnma
9.AF.23	Boromullite	Al₉BSi₂O₁₉	Orth. mm2 : Cmc2₁
9.AF.25	Yoderite	Mg(Al,Fe³⁺)₃(SiO₄)₂O(OH)	Mon. 2/m : P2₁/m
9.AF.30	Magnesiostaurolite	Mg(Mg,Li)₃(Al,Mg)₁₈Si₈O₄₄(OH)₄	Mon. 2/m : B2/m
9.AF.30	Staurolite	Fe²⁺₂Al₉Si₄O₂₃(OH)	Mon. 2/m : B2/m
9.AF.30	Zincostaurolite	Zn₂Al₉Si₄O₂₃(OH)	Mon. 2/m : B2/m
9.AF.35	Topaz	Al₂(SiO₄)(F,OH)₂	Orth. mmm (2/m 2/m 2/m)
9.AF.40	Norbergite	Mg₃(SiO₄)F₂	Orth. mmm (2/m 2/m 2/m)
9.AF.45	Alleghanyite	Mn²⁺₅(SiO₄)₂(OH)₂	Mon. 2/m : P2₁/b
9.AF.45	Chondrodite	Mg₅(SiO₄)₂F₂	Mon. 2/m : P2₁/b
9.AF.45	Reinhardbraunsite	Ca₅(SiO₄)₂(OH,F)₂	Mon. 2/m : P2₁/b
9.AF.45	Kumtyubeite	Ca₅(SiO₄)₂F₂	Mon. 2/m : P2₁/b
9.AF.45	Hydroxylchondrodite	Mg₅(SiO₄)₂(OH)₂	Mon. 2/m : P2₁/b
9.AF.50	Humite	Mg₇(SiO₄)₃F₂	Orth. mmm (2/m 2/m 2/m) : Pnma
9.AF.50	Manganhumite	(Mn²⁺,Mg)₇(SiO₄)₃(OH)₂	Orth. mmm (2/m 2/m 2/m)
9.AF.50	Unnamed (Ca-analogue of Humite)	Ca₇(SiO₄)₄F₂	Orth. mmm (2/m 2/m 2/m)
9.AF.50	Fluorchegemite	Ca₇(SiO₄)₃F₂	Orth. mmm (2/m 2/m 2/m)
9.AF.50	Unnamed (OH-analogue of humite)	Mg₇(SiO₄)₃(OH)₂	Orth.
9.AF.55	Clinohumite	Mg₉(SiO₄)₄F₂	Mon. 2/m : P2₁/b
9.AF.55	Sonolite	Mn²⁺₉(SiO₄)₄(OH)₂	Mon. 2/m : P2₁/b
9.AF.55	Hydroxylclinohumite	Mg₉(SiO₄)₄(OH)₂	Mon. 2/m : P2₁/b
9.AF.60	Leucophoenicite	Mn²⁺₇(SiO₄)₃(OH)₂	Mon. 2/m : P2₁/b
9.AF.65	Ribbeite	Mn²⁺₅(SiO₄)₂(OH)₂	Orth. mmm (2/m 2/m 2/m)
9.AF.70	Jerrygibbsite	Mn²⁺₉(SiO₄)₄(OH)₂	Orth. mmm (2/m 2/m 2/m) : Pbcn
9.AF.75	Franciscanite	Mn²⁺₆(V⁵⁺,◻)₂(SiO₄)₂(O,OH)₆	Trig. 3 : P3
9.AF.75	Örebroite	Mn²⁺₃(Sb⁵⁺,Fe³⁺)(SiO₄)(O,OH)₃	Trig. 3 : P3
9.AF.75	Welinite	Mn²⁺₆(W⁶⁺,Mg)₂(SiO₄)₂(O,OH)₆	Trig. 3 : P3
9.AF.75	Scorticoite	Mn₆(Sb,◻)_Σ2(SiO₄)₂O₃(OH)₃	Trig. 3 : P3
9.AF.80	Ellenbergerite	Mg₆(Mg,Ti,Zr,◻)₂(Al,Mg)₆Si₈O₂₈(OH)₁₀	Hex. 6 : P6₃
9.AF.85	Chloritoid	(Fe²⁺,Mg,Mn²⁺)Al₂(SiO₄)O(OH)₂	Mon. 2/m : B2/b
9.AF.85	Magnesiochloritoid	MgAl₂(SiO₄)O(OH)₂	Mon. 2/m : B2/b
9.AF.85	Ottrélite	(Mn²⁺,Fe²⁺,Mg)Al₂(SiO₄)O(OH)₂	Mon.
9.AF.90	Poldervaartite	CaCa[SiO₃(OH)](OH)	Orth. mmm (2/m 2/m 2/m) : Pbca
9.AF.95	Pilawite-(Y)	Ca₂Y₂Al₄(SiO₄)₄O₂(OH)₂	Mon. 2/m : P2₁/b

Fluorescence of OlmiiteHide

In UV light:

Deep red (SW UV)

Other InformationHide

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 OlmiiteHide

mindat.org URL:

https://www.mindat.org/min-30762.html
Please feel free to link to this page.

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External Links:

Look for Olmiite on Webmineral

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Raman and XRD data at RRUFF project

References and PDF downloads at RRUFF project

American Mineralogist Crystal Structure Database

Handbook of Mineralogy page PDF

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References for OlmiiteHide

Reference List:

Pagano, R., Guastoni, A., Pezzotta, F. (2008) Olmiite and poldervaartite from the Kalahari manganese field northern cape province republic of South Africa. The Mineralogical Record: 39(5): 373.

Cook, Robert B. (2012) Connoisseur's Choice: Olmiite, N'Chwaning II Mine, Kalahari Manganese Field, Republic of South Africa. Rocks & Minerals, 87 (2) 150-155 doi:10.1080/00357529.2012.657988

Frost, Ray L., Scholz, Ricardo, López, Andrés, Xi, Yunfei, Granja, Amanda, Žigovečki Gobac, Željka, Lima, Rosa Malena Fernandes (2013) Infrared and Raman spectroscopic characterization of the silicate mineral olmiite CaMn²⁺[SiO₃(OH)](OH) – implications for the molecular structure. Journal of Molecular Structure, 1053. 22-26 doi:10.1016/j.molstruc.2013.08.038

(2023) Olmiite. Handbook of Mineralogy. Mineralogical Society of America

Localities for OlmiiteHide

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the

symbol to view information about a locality. The

symbol next to localities in the list can be used to jump to that position on the map.

Locality ListHide

- 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.


South Africa (TL)
Northern Cape John Taolo Gaetsewe District Municipality Joe Morolong Local Municipality N'Chwaning Mines ⓘ N'Chwaning II Mine (TL)	Bonazzi et al. (2007)
ⓘ N'Chwaning III Mine	P.Rondelez
ⓘ Wessels Mine	www.mindat.org (2009)

Spain
Canary Islands Santa Cruz de Tenerife Province Tenerife ⓘ Tajao	Dill et al. (2023)

Sweden
Värmland County Filipstad Långban Ore District ⓘ Långban Mine

Olmiite

About OlmiiteHide

Unique IdentifiersHide

IMA Classification of OlmiiteHide

Classification of OlmiiteHide

Mineral SymbolsHide

Pronunciation of OlmiiteHide

Physical Properties of OlmiiteHide

Optical Data of OlmiiteHide

Chemistry of OlmiiteHide

Crystallography of OlmiiteHide

Crystal StructureHide

X-Ray Powder DiffractionHide

Geological EnvironmentHide

Type Occurrence of OlmiiteHide

Synonyms of OlmiiteHide

Relationship of Olmiite to other SpeciesHide

Common AssociatesHide

Related Minerals - Strunz-mindat GroupingHide

Fluorescence of OlmiiteHide

Other InformationHide

Internet Links for OlmiiteHide

References for OlmiiteHide

Localities for OlmiiteHide

Locality ListHide

Related Minerals - Strunz-mindat Grouping Hide