Castellaroite
A valid IMA mineral species
This page is currently not sponsored. Click here to sponsor this page.
About Castellaroite
My friend Fabrizio Castellaro
Formula:
Mn2+3(AsO4)2 · 4H2O
Colour:
colorless
Lustre:
Vitreous, Silky
Hardness:
3½
Specific Gravity:
3.14
Crystal System:
Monoclinic
Name:
Named in honour of the mineral collector Fabrizio Castellaro who has discovered castellaroite, but also balestraite, cerchiaraite-(Fe) and lavinskyite-1M.
Probably a polymorph of sterlinghillite. Structurally related to metaswitzerite.
A higher hydrate (octahydrate) is manganohörnesite.
A higher hydrate (octahydrate) is manganohörnesite.
Unique Identifiers
Mindat ID:
46905
Long-form identifier:
mindat:1:1:46905:0
Classification of Castellaroite
IMA Classification of Castellaroite
Approved
IMA Formula:
Mn2+3(As5+O4)2·4.5H2O
Approval year:
2015
8.CD.
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
D : With only medium-sized cations, RO4:H2O = 1:2
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
D : With only medium-sized cations, RO4:H2O = 1:2
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 |
|---|---|---|
| Ctr | 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 Castellaroite
Vitreous, Silky
Transparency:
Transparent
Colour:
Colorless
Streak:
White
Hardness:
3½ on Mohs scale
Tenacity:
Flexible
Cleavage:
Perfect
{001}
{001}
Density:
3.14(2) g/cm3 (Measured) 3.164 g/cm3 (Calculated)
Optical Data of Castellaroite
Type:
Biaxial (-)
RI values:
nα = 1.644(1) nβ = 1.662(1) nγ = 1.667(1)
2V:
Measured: 57° (1)
Birefringence:
0.023
Max. Birefringence:
δ = 0.023
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
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
moderate r < v
Chemistry of Castellaroite
Mindat Formula:
Mn2+3(AsO4)2 · 4H2O
Element Weights:
Elements listed:
Crystallography of Castellaroite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Cell Parameters:
a = 8.752(2) Å, b = 13.463(4) Å, c = 18.636(6) Å
β = 94.851(7)°
β = 94.851(7)°
Ratio:
a:b:c = 0.65 : 1 : 1.384
Unit Cell V:
2,187.98 ų (Calculated from Unit Cell)
Z:
8
Morphology:
Thin blades, flattened on [001], striated and elongated parallel to [100] and exhibiting the forms {110}, {012} and {001}.
Comment:
P21/n
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 10.9056 Å | (100) |
| 9.2922 Å | (84) |
| 7.6485 Å | (4) |
| 6.9849 Å | (28) |
| 6.6529 Å | (22) |
| 5.6280 Å | (3) |
| 5.5618 Å | (5) |
| 5.1963 Å | (7) |
| 4.7313 Å | (5) |
| 4.5714 Å | (10) |
| 4.3624 Å | (7) |
| 4.1487 Å | (3) |
| 4.0424 Å | (8) |
| 3.9920 Å | (2) |
| 3.8721 Å | (2) |
| 3.8258 Å | (6) |
| 3.7207 Å | (8) |
| 3.6352 Å | (11) |
| 3.6172 Å | (3) |
| 3.5963 Å | (22) |
| 3.4158 Å | (18) |
| 3.3244 Å | (22) |
| 3.3131 Å | (3) |
| 3.2285 Å | (6) |
| 3.2229 Å | (2) |
| 3.1286 Å | (7) |
| 3.1261 Å | (12) |
| 3.0878 Å | (3) |
| 3.0534 Å | (50) |
| 3.0213 Å | (15) |
| 2.9773 Å | (6) |
| 2.9583 Å | (5) |
Comments:
KAMPF, ANTHONY R., CÁMARA, FERNANDO, CIRIOTTI, MARCO E., NASH, BARBARA P., BALESTRA, CORRADO, and CHIAPPINO, LUIGI (2016) Castellaroite, Mn2+3(AsO4)2· 4.5 H2O, a new mineral from Italy related to metaswitzerite, European Journal of Mineralogy, 28, 687-696.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 46 : Near-surface hydrothermal alteration of minerals (see also #22) | |
| 47a : [Near-surface hydration of prior minerals] | |
| 47d : [Arsenates, antimonates, selenates, bismuthinates] | |
| 47e : [Vanadates, chromates, manganates] | |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 55 : Anthropogenic mine minerals |
Type Occurrence of Castellaroite
Co-Type Localities:
General Appearance of Type Material:
thin blades, flattened on [001], striated and elongated parallel to [100] and exhibiting the forms {110}, {012} and {001}.
Place of Conservation of Type Material:
Type material is deposited in the mineralogical collections of the Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA, cataloguenumbers 65603 (holotype - MN) and 65604 (cotype - MN), and the Museo Regionale
Geological Setting of Type Material:
Secondary arsenate mineral
Associated Minerals at Type Locality:
Synonyms of Castellaroite
Other Language Names for Castellaroite
Dutch:Castellaroiet
German:Castellaroit
Common Associates
Associations Based on Photo Data:
| 1 photo of Castellaroite associated with Wallkilldellite | Ca2Mn2+3(AsO4)2(OH)4 · 9H2O |
Related Minerals - Strunz-mindat Grouping
| 8.CD. | Sergeysmirnovite | MgZn2(PO4)2 · 4H2O |
| 8.CD.05 | Phosphosiderite | FePO4 · 2H2O |
| 8.CD.05 | Metavariscite | AlPO4 · 2H2O |
| 8.CD.05 | Bonacinaite | Sc(AsO4) · 2H2O |
| 8.CD.05 | Kolbeckite | ScPO4 · 2H2O |
| 8.CD.10 | Yanomamite | InAsO4 · 2H2O |
| 8.CD.10 | Mansfieldite | AlAsO4 · 2H2O |
| 8.CD.10 | Scorodite | Fe3+AsO4 · 2H2O |
| 8.CD.10 | Variscite | AlPO4 · 2H2O |
| 8.CD.10 | Strengite | FePO4 · 2H2O |
| 8.CD.15 | Parascorodite | FeAsO4 · 2H2O |
| 8.CD.20 | Ludlamite | Fe2+3(PO4)2 · 4H2O |
| 8.CD.25 | Sterlinghillite | Mn2+3(AsO4)2 · 3H2O |
| 8.CD.30 | Rollandite | Cu3(AsO4)2 · 4H2O |
| 8.CD.35 | Liversidgeite | Zn6(PO4)4 · 7H2O |
| 8.CD.40 | Thorasphite | Th2H(PO4,AsO4)3 · 6H2O |
Other Information
Notes:
easily soluble in dilute HCl at room temperature
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 Castellaroite
mindat.org URL:
https://www.mindat.org/min-46905.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 Castellaroite
Reference List:
Hålenius, U., Hatert, F., Pasero, M., Mills, S. J. (2015) New minerals and nomenclature modifications approved in 2015, CNMNC Newsletter no 28. Mineralogical Magazine, 79 (7) 1859-1864 doi:10.1180/minmag.2015.079.7.18
Localities for Castellaroite
Showing 5 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.
Italy | |
| Castellaro et al. (2021) |
| Hålenius et al. (2015) +1 other reference |
| Hålenius et al. (2015) +1 other reference |
Switzerland | |
| Ansermet et al. (2026) |
USA | |
| Earl Verbeek |
Quick NavTopAbout CastellaroiteUnique IdentifiersClassification IMA Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Monte Nero Mine, Rocchetta di Vara, La Spezia Province, Liguria, Italy