Quick Links : The Mindat Manual The Rock H. Currier Digital Library Mindat Newsletter [Free Download]

Home Page About Mindat The Mindat Manual History of Mindat Copyright Status Who We Are Contact Us Advertise on Mindat

Donate to Mindat Corporate Sponsorship Sponsor a Page Sponsored Pages Mindat Advertisers Advertise on Mindat

Learning Center What is a mineral?The most common minerals on earth Information for Educators Mindat Articles The Elements The Rock H. Currier Digital Library Geologic Time Explore Fossils

Minerals by Properties Minerals by Chemistry Mineral Visual Explorer Advanced Locality Search Random Mineral Random Locality Search by minID Localities Near Me Search Articles Search Glossary More Search Options

The Mindat Manual Add a New Photo Rate Photos Locality Edit Report Coordinate Completion Report Add Glossary Item

Mining Companies Statistics Users Mineral Museums Clubs & Organizations Mineral Shows & Events The Mindat Directory Device Settings The Mineral Quiz Time Machine

Photo Search Photo Galleries Search by Color Photo Colour Explorer New Photos Today New Photos Yesterday Members' Photo Galleries Past Photo of the Day Gallery Photography

Guidottiite

A valid IMA mineral species

This page is currently not sponsored. Click here to sponsor this page.

Discuss Guidottiite

Search Photos of Guidottiite

Edit Guidottiite Add Synonym Edit CIF structures Clear Cache

Guidottiite

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

Guidottiite

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

Guidottiite

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

Hide all sections | Show all sections

About GuidottiiteHide

Charles V. Guidotti

Formula:

Mn₂Fe³⁺(Fe³⁺SiO₅)(OH)₄

Colour:

Black

Lustre:

Vitreous, Silky

Hardness:

4 - 4½

Specific Gravity:

3.33

Crystal System:

Hexagonal

Member of:

Serpentine Subgroup > Kaolinite-Serpentine Group

Name:

Named in honour of Charles V. Guidotti (19 September 1935, Somerville, Massachusetts, USA - 19 May 2005, Boston, Massachusetts, USA), professor at the University of California, Davis (1962–1969), the University of Wisconsin–Madison (1969–1981), and the University of Maine (1981–2005), for his many contributions to phyllosilicate mineralogy. He also made important contributions to the petrologic studies of metamorphic rocks in the northern Appalachian Mountains of Maine.

Type Locality:

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

Isostructural with:

Cronstedtite

Serpentine Group. The Mn-analogue of Cronstedtite. Compare 'UM1969-14-SiO:FeHMn'.

Unique IdentifiersHide

Mindat ID:

39763

Long-form identifier:

mindat:1:1:39763:8

IMA Classification of GuidottiiteHide

IMA status:

Approved

IMA Formula:

Mn²⁺₂Fe³⁺(SiFe³⁺)O₅(OH)₄

Approval year:

2009

First published:

2010

Type description reference:

Wahle, Michael W.; Bujnowski, Thomas J.; Guggenheim, Stephen; Kogure, Toshihiro (2010) Guidottiite, the Mn-analogue of cronstedtite: a new serpentine-group mineral from South Africa. Clays and Clay Minerals, 58 (3). 364-376 doi:10.1346/ccmn.2010.0580307

Classification of GuidottiiteHide

Strunz-mindat (2026):

9.ED.15

9 : SILICATES (Germanates)
E : Phyllosilicates
D : Phyllosilicates with kaolinite layers composed of tetrahedral and octahedral nets

Dana 8th ed.:

71.1.4.8

71 : PHYLLOSILICATES Sheets of Six-Membered Rings
1 : Sheets of 6-membered rings with 1:1 layers

Mineral SymbolsHide

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

Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.

Symbol	Source	Reference for Standard
Gdt	IMA–CNMNC	Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43
Gdt	Warr (2020)	Warr, L.N. (2020) Recommended abbreviations for the names of clay minerals and associated phases. Clay Minerals, 55, 261–264 doi:10.1180/clm.2020.30

Physical Properties of GuidottiiteHide

Lustre:

Vitreous, Silky

Transparency:

Opaque

Comment:

Vitreous in bulk, silky under magnification

Colour:

Black

Hardness:

4 - 4½ on Mohs scale

Cleavage:

Perfect
(001)

Density:

3.33 g/cm³ (Measured) 3.264(27) g/cm³ (Calculated)

Comment:

Measured on bulk sample with impurities. Calculated value is based on sets of microprobe analyses.

Chemistry of GuidottiiteHide

Mindat Formula:

Mn₂Fe³⁺(Fe³⁺SiO₅)(OH)₄

Element Weights:

Element	% weight
O	36.209 %
Fe	28.086 %
Mn	27.629 %
Si	7.062 %
H	1.014 %

Calculated from ideal end-member formula.

Elements listed:

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

Crystallography of GuidottiiteHide

Crystal System:

Hexagonal

Class (H-M):

6 - Pyramidal

Space Group:

P6₃

Setting:

P6₃

Cell Parameters:

a = 5.5472(3) Å, c = 14.296(2) Å

Ratio:

a:c = 1 : 2.577

Unit Cell V:

380.97 Å³ (Calculated from Unit Cell)

Crystal StructureHide

Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4

View
CIF File Best | x | y | z | a | b | c

Rotation
Stop | Start

Labels
Console Off | On | Grey | Yellow

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)
0018323	Guidottiite	Wahle M W, Bujnowski T J, Guggenheim S, Kogure T (2010) Guidottiite, the Mn-analogue of cronstedtite: A new serpentine-group mineral from South Africa Clays and Clay Minerals 58 364-376		2010	N'chwaning 2 mine, Kalahari manganese field, South Africa	0	293

CIF Raw Data - click here to close

data_global
_chemical_name_mineral 'Guidottiite'
loop_
_publ_author_name
'Wahle M W'
'Bujnowski T J'
'Guggenheim S'
'Kogure T'
_journal_name_full 'Clays and Clay Minerals'
_journal_volume 58 
_journal_year 2010
_journal_page_first 364
_journal_page_last 376
_publ_section_title
;
 Guidottiite, the Mn-analogue of cronstedtite: A new serpentine-group
 mineral from South Africa
;
_database_code_amcsd 0018323
_chemical_compound_source 'N'chwaning 2 mine, Kalahari manganese field, South Africa'
_chemical_formula_sum 'Mn1.854 Fe1.656 Mg.537 Si.953 O9 H4'
_cell_length_a 5.5472
_cell_length_b 5.5472
_cell_length_c 14.296
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 380.972
_exptl_crystal_density_diffrn      3.332
_symmetry_space_group_name_H-M 'P 63'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  'x-y,x,1/2+z'
  '-y,x-y,z'
  '-x,-y,1/2+z'
  '-x+y,-x,z'
  'y,-x+y,1/2+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
MnM1   0.66700  -0.00080   0.23750   0.61800   0.01390
Fe3+M1   0.66700  -0.00080   0.23750   0.20300   0.01390
MgM1   0.66700  -0.00080   0.23750   0.17900   0.01390
SiT1   0.00000   0.00000   0.03820   0.32200   0.00900
Fe3+T1   0.00000   0.00000   0.03820   0.67800   0.00900
SiT2   0.33333   0.66667   0.03660   0.63100   0.00950
Fe3+T2   0.33333   0.66667   0.03660   0.36900   0.00950
O1   0.19100   0.33200   0.00000   1.00000   0.01900
O4   0.00000   0.00000   0.15700   1.00000   0.00670
O5   0.33333   0.66667   0.15770   1.00000   0.00730
O-H1   0.66667   0.33333   0.15920   1.00000   0.00520
O-H2   0.33500   0.00100   0.30810   1.00000   0.00870
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
MnM1 0.01380 0.01380 0.01410 0.00700 0.00010 0.00030
Fe3+M1 0.01380 0.01380 0.01410 0.00700 0.00010 0.00030
MgM1 0.01380 0.01380 0.01410 0.00700 0.00010 0.00030
SiT1 0.00860 0.00860 0.00970 0.00430 0.00000 0.00000
Fe3+T1 0.00860 0.00860 0.00970 0.00430 0.00000 0.00000
SiT2 0.00880 0.00880 0.01100 0.00440 0.00000 0.00000
Fe3+T2 0.00880 0.00880 0.01100 0.00440 0.00000 0.00000
O4 0.00960 0.00960 0.00100 0.00480 0.00000 0.00000
O5 0.00740 0.00740 0.00700 0.00370 0.00000 0.00000
O-H1 0.00680 0.00680 0.00200 0.00340 0.00000 0.00000
O-H2 0.01000 0.01300 0.00200 0.00500 0.00200 0.00100

X-Ray Powder DiffractionHide

Powder Diffraction Data:

d-spacing	Intensity
7.1480 Å	(100)
4.8040 Å	(13.97)
4.5538 Å	(41.49)
3.9872 Å	(16.69)
3.5740 Å	(74.03)
3.3832 Å	(16.78)
2.8675 Å	(5.82)
2.7736 Å	(1.07)
2.7228 Å	(39.02)
2.5858 Å	(95.46)
2.4570 Å	(5.28)
2.3971 Å	(42.37)
2.3827 Å	(4.65)
2.1912 Å	(13.14)
2.1449 Å	(1.27)
2.1345 Å	(1.79)
1.9936 Å	(1.07)
1.9908 Å	(40.42)
1.8795 Å	(1.52)
1.8391 Å	(1.68)
1.8157 Å	(1.07)
1.8073 Å	(13.58)
1.8013 Å	(2.68)
1.8013 Å	(1.81)
1.7870 Å	(1.79)
1.7599 Å	(1.62)
1.6967 Å	(1.93)
1.6967 Å	(1.45)
1.6446 Å	(19.72)
1.6188 Å	(1.06)
1.6013 Å	(33.47)
1.5626 Å	(13.12)
1.5559 Å	(1.40)
1.5328 Å	(1.05)
1.5022 Å	(18.31)
1.4614 Å	(12.58)
1.4296 Å	(3.25)
1.3803 Å	(3.45)
1.3784 Å	(8.98)
1.3614 Å	(14.14)
1.3316 Å	(4.80)
1.3291 Å	(5.14)
1.2707 Å	(1.63)
1.2478 Å	(5.38)
1.1986 Å	(4.55)
1.1768 Å	(2.77)
1.1473 Å	(4.31)
1.0956 Å	(4.28)
1.0946 Å	(2.55)

Locality:

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

Reference:

Comments:

Wahle M W, Bujnowski T J, Guggenheim S, Kogure T. (2010) Guidottiite, the Mn-analogue of cronstedtite: A new serpentine-group mineral from South Africa, Clays and Clay Minerals, 58, 364-376.

Geological EnvironmentHide

Paragenetic Mode(s):

Paragenetic Mode	Earliest Age (Ga)
High-? alteration and/or metamorphism
32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits

Type Occurrence of GuidottiiteHide

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:

Columnar, with grains, ranging in size up to ~3 mm; poorly adhered to each other.

Place of Conservation of Type Material:

National Museum of Natural History (Smithsonian Institution), Washington, D.C., USA, NMNH 174879.

Geological Setting of Type Material:

Stratiform manganese deposit.

Reference:

Synonyms of GuidottiiteHide

IMA2009-061

Other Language Names for GuidottiiteHide

Dutch:Guidottiiet

German:Guidottiit

Relationship of Guidottiite to other SpeciesHide

Member of:

Serpentine Subgroup > Kaolinite-Serpentine Group

Other Members of Serpentine Subgroup:

Amesite	Mg₂Al(AlSiO₅)(OH)₄	Tric. 1 : P1
Antigorite	Mg₃(Si₂O₅)(OH)₄	Mon. m : Bm
Berthierine	(Fe²⁺,Fe³⁺,Al)₃(Si,Al)₂O₅(OH)₄	Mon. m : Bm
Brindleyite	(Ni,Al)₃(Si,Al)₂O₅(OH)₄	Mon.
Caryopilite	Mn²⁺₃Si₂O₅(OH)₄	Mon.
Chrysotile	Mg₃(Si₂O₅)(OH)₄	Mon. m : Bb
Cronstedtite	Fe²⁺₂Fe³⁺((Si,Fe³⁺)₂O₅)(OH)₄	Trig. 3m : P31m
Fraipontite	(Zn,Al)₃((Si,Al)₂O₅)(OH)₄	Mon.
Kellyite	Mn²⁺₂Al(AlSiO₅)(OH)₄	Hex. 6 : P6₃
Lizardite	Mg₃(Si₂O₅)(OH)₄	Trig. 3m : P31m
Népouite	Ni₃Si₂O₅(OH)₄	Orth.
Pecoraite	Ni₃(Si₂O₅)(OH)₄	Mon.

Related Minerals - Strunz-mindat Grouping Hide

9.ED.	'Clinochrysotile'	Mg₃(Si₂O₅)(OH)₄	Mon. 2/m
9.ED.05	Dickite	Al₂(Si₂O₅)(OH)₄	Mon. m : Bb
9.ED.05	Nacrite	Al₂(Si₂O₅)(OH)₄	Mon. m : Bb
9.ED.05	Kaolinite	Al₂(Si₂O₅)(OH)₄	Tric. 1 : P1
9.ED.05	Odinite	(Fe,Mg,Al,Fe,Ti,Mn)_2.4((Si,Al)₂O₅)(OH)₄	Mon. m : Bm
9.ED.10	Halloysite	Al₂Si₂O₅(OH)₄ · n(H₂O)	Mon. m : Bb
9.ED.10	Hisingerite	Fe³⁺₂(Si₂O₅)(OH)₄ · 2H₂O	Mon.
9.ED.10	'Hydrohalloysite'	Al₂Si₂O₅(OH)₄ · 2H₂O	Mon. m
9.ED.15	Antigorite	Mg₃(Si₂O₅)(OH)₄	Mon. m : Bm
9.ED.15	Brindleyite	(Ni,Al)₃(Si,Al)₂O₅(OH)₄	Mon.
9.ED.15	Fraipontite	(Zn,Al)₃((Si,Al)₂O₅)(OH)₄	Mon.
9.ED.15	Népouite	Ni₃Si₂O₅(OH)₄	Orth.
9.ED.15	Pecoraite	Ni₃(Si₂O₅)(OH)₄	Mon.
9.ED.15	Lizardite	Mg₃(Si₂O₅)(OH)₄	Trig. 3m : P31m
9.ED.15	Berthierine	(Fe²⁺,Fe³⁺,Al)₃(Si,Al)₂O₅(OH)₄	Mon. m : Bm
9.ED.15	Kellyite	Mn²⁺₂Al(AlSiO₅)(OH)₄	Hex. 6 : P6₃
9.ED.15	Cronstedtite	Fe²⁺₂Fe³⁺((Si,Fe³⁺)₂O₅)(OH)₄	Trig. 3m : P31m
9.ED.15	Caryopilite	Mn²⁺₃Si₂O₅(OH)₄	Mon.
9.ED.15	Amesite	Mg₂Al(AlSiO₅)(OH)₄	Tric. 1 : P1
9.ED.15	Greenalite	(Fe²⁺,Fe³⁺)_2-3Si₂O₅(OH)₄	Mon.
9.ED.15	Manandonite	Li₂Al₄(Si₂AlB)O₁₀(OH)₈	Orth. 222 : C222₁
9.ED.20	Chrysocolla	Cu_2-xAl_x(H_2-xSi₂O₅)(OH)₄ · nH₂O, x < 1	Orth.
9.ED.20	Neotocite	(Mn,Fe)SiO₃ · H₂O (?)	Amor.
9.ED.20	Allophane	(Al₂O₃)(SiO₂)_1.3-2 · 2.5-3H₂O	Amor.
9.ED.20	Imogolite	Al₂SiO₃(OH)₄
9.ED.25	Bismutoferrite	Fe³⁺₂Bi(SiO₄)₂(OH)	Mon. m : Bm
9.ED.25	Chapmanite	Fe³⁺₂Sb³⁺(Si₂O₅)O₃(OH)	Mon. m : Bm
9.ED.30	'Pianlinite'	Al₂Si₂O₆(OH)₂	Orth.

Fluorescence of GuidottiiteHide

In UV light:

Not fluorescent in 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 GuidottiiteHide

mindat.org URL:

https://www.mindat.org/min-39763.html
Please feel free to link to this page.

Search Engines:

Look for Guidottiite on Google

Look for Guidottiite images on Google

Look for Guidottiite on Bing

Look for Guidottiite images on Bing

Look for Guidottiite on DuckDuckGo

Look for Guidottiite images on DuckDuckGo

Look for Guidottiite in the Rock H. Currier Digital Library

External Links:

Look for Guidottiite on Webmineral

Look for Guidottiite on Wikipedia

Look for Guidottiite on Mineralien Atlas

Raman and XRD data at RRUFF project

References and PDF downloads at RRUFF project

American Mineralogist Crystal Structure Database

Handbook of Mineralogy page PDF

Mineral Dealers:

Buy from D. Joyce minerals

References for GuidottiiteHide

Reference List:

Williams, P.A., Hatert, F., Pasero, M. (2009) New minerals approved in 2009. in International Mineralogical Association, 1-34.

Belakovskiy, D., Gatta, G. D., Camara, F. (2014) New Mineral Names. American Mineralogist, 99 (1) 242-247 doi:10.2138/am.2014.629

(2014) Guidottiite. Handbook of Mineralogy. Mineralogical Society of America

Localities for GuidottiiteHide

Showing 1 localities.

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.

Hide all sections | Show all sections

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)

Wahle et al. (2010)

Mindat.org® is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization. Mindat® and mindat.org® are registered trademarks of the Hudson Institute of Mineralogy.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2026, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph and Ida Chau.
Content on this site may not be used to train, fine-tune, or otherwise develop artificial intelligence or machine learning models without prior written permission - see our Terms & Conditions.
To cite: Ralph, J., Von Bargen, D., Martynov, P., Zhang, J., Que, X., Prabhu, A., Morrison, S. M., Li, W., Chen, W., & Ma, X. (2025). Mindat.org: The open access mineralogy database to accelerate data-intensive geoscience research. American Mineralogist, 110(6), 833–844. doi:10.2138/am-2024-9486.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: September 23, 2026 11:02:50 Page updated: September 15, 2026 19:44:23

Go to top of page

Guidottiite

About GuidottiiteHide

Unique IdentifiersHide

IMA Classification of GuidottiiteHide

Classification of GuidottiiteHide

Mineral SymbolsHide

Physical Properties of GuidottiiteHide

Chemistry of GuidottiiteHide

Crystallography of GuidottiiteHide

Crystal StructureHide

X-Ray Powder DiffractionHide

Geological EnvironmentHide

Type Occurrence of GuidottiiteHide

Synonyms of GuidottiiteHide

Other Language Names for GuidottiiteHide

Relationship of Guidottiite to other SpeciesHide

Related Minerals - Strunz-mindat GroupingHide

Fluorescence of GuidottiiteHide

Other InformationHide

Internet Links for GuidottiiteHide

References for GuidottiiteHide

Localities for GuidottiiteHide

Locality ListHide

Related Minerals - Strunz-mindat Grouping Hide