Named for its structural relation to caseyite. The describing authors speculate that the tetramer in protocaseyite is genetically related to caseyite.

Type Locality:

ⓘ Burro Mine, Slick Rock Mining District, San Miguel County, Colorado, USA

Decavanadate family. Compare, e.g., bariandite, bokite; vanalite.

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Unique IdentifiersHide

Mindat ID:

55381

Long-form identifier:

mindat:1:1:55381:8

GUID
(UUID V4):

e306887b-1b96-431e-861e-4467c7eb075d

IMA Classification of ProtocaseyiteHide

IMA status:

Approved

Approval year:

2021

First published:

2022

Classification of ProtocaseyiteHide

Strunz-mindat (2024):

4.HC.

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
H : V[5,6] Vanadates
C : [6]-Sorovanadates

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
Pcy	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 ProtocaseyiteHide

Lustre:

Vitreous

Colour:

Saffron yellow

Streak:

Orange yellow

Hardness:

2 on Mohs scale

Tenacity:

Brittle

Cleavage:

Very Good
Two very good cleavages. One on {111} and one along the length of the blades and at an angle to the {111} face - possibly on {010}.

Fracture:

Sub-Conchoidal

Comment:

curved

Density:

2.45(2) g/cm³ (Measured) 2.448 g/cm³ (Calculated)

Optical Data of ProtocaseyiteHide

Type:

Biaxial

RI values:

n_α = 1.755(5) n_β = 1.800 n_γ = 1.800

Max Birefringence:

δ = 0.045

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

Surface Relief:

Very High

Dispersion:

Extreme.

Pleochroism:

Visible

Comments:

X = Y = yellow; Z = orange.

Comments:

Absorption: X ≈ Y < Z.

Chemistry of ProtocaseyiteHide

Mindat Formula:

[Al₄(OH)₆(H₂O)₁₂][V₁₀O₂₈] · 8H₂O

Elements listed:

Al, H, O, V - search for minerals with similar chemistry

Crystallography of ProtocaseyiteHide

Crystal System:

Triclinic

Class (H-M):

1 - Pinacoidal

Space Group:

Cell Parameters:

a = 9.435(2) Å, b = 10.742(3) Å, c = 11.205(3) Å
α = 75.395(7)°, β = 71.057(10)°, γ = 81.286(6)°

Ratio:

a:b:c = 0.878 : 1 : 1.043

Unit Cell V:

1,036.41 Å³ (Calculated from Unit Cell)

X-Ray Powder DiffractionHide

Powder Diffraction Data:

d-spacing	Intensity
10.38 Å	(100)
8.89 Å	(37)
8.15 Å	(13)
7.24 Å	(38)
5.922 Å	(17)
2.177 Å	(11)
2.083 Å	(13)
1.785 Å	(11)

Type Occurrence of ProtocaseyiteHide

Type Locality:

ⓘ Burro Mine, Slick Rock Mining District, San Miguel County, Colorado, USA

General Appearance of Type Material:

Thick blades.

Place of Conservation of Type Material:

Mineralogical collections of the Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA, catalogue numbers 75191, 75192 and 75193 (cotypes).

Geological Setting of Type Material:

Part of a low-temperature, post-mining, secondary mineral assemblage.

Associated Minerals at Type Locality:

Synonyms of ProtocaseyiteHide

IMA2020-090

Related Minerals - Strunz-mindat Grouping Hide

4.HC.	Beckettite	Ca₂V₆Al₆O₂₀	Tric. 1 : P1
4.HC.	Ammoniolasalite	(NH₄)₂Mg₂(H₂O)₂₀] [V₁₀O₂₈]	Mon. 2/m : B2/b
4.HC.05	Pascoite	Ca₂Ca(V₁₀O₂₈) · 17H₂O	Mon. 2 : B2
4.HC.05	Lasalite	Na₂Mg₂(V₁₀O₂₈) · 20H₂O	Mon. 2/m : B2/b
4.HC.05	Magnesiopascoite	Ca₂Mg(V₁₀O₂₈) · 16H₂O	Mon. 2/m : B2/m
4.HC.05	Rakovanite	(NH₄)₃Na₃(V₁₀O₂₈) · 12H₂O	Mon. 2/m
4.HC.05	Hughesite	Na₃Al(V₁₀O₂₈) · 22H₂O	Tric. 1 : P1
4.HC.05	Hydropascoite	Ca₃(V₁₀O₂₈) · 24H₂O	Tric. 1 : P1
4.HC.10	Hummerite	K₂Mg₂(V₁₀O₂₈) · 16H₂O	Tric. 1 : P1
4.HC.15	Sherwoodite	Ca_5.5(AlV⁴⁺V⁵⁺₁₂O₃₉) · 28H₂O	Tet. 4/mmm (4/m 2/m 2/m) : I4₁/amd
4.HC.20	Bluestreakite	K₄Mg₂(V⁴⁺₂V⁵⁺₈O₂₈) · 14H₂O	Mon. 2/m
4.HC.25	Wernerbaurite	{(NH₄)₂[Ca₂(H₂O)₁₄](H₂O)₂}{V₁₀O₂₈}	Tric. 1 : P1
4.HC.25	Burroite	Ca₂(NH₄)₂(V₁₀O₂₈) · 15H₂O	Tric. 1 : P1
4.HC.30	Caseyite	[(V⁵⁺O₂)Al_10-x(OH)_20-2x(H₂O)_18-2x]₂[H₂V⁴⁺V⁵⁺₉O₂₈][V⁵⁺₁₀O₂₈]₂(Na,K,Ca)_2-y(SO₄)_2-z · (60+8x+y+4z)H₂O (x = 0-2.5; y = 0-2; z = 0-2)	Mon.
4.HC.35	Gunterite	Na₄Ca(V₁₀O₂₈) · 20H₂O	Mon. 2/m : B2/m
4.HC.40	Kokinosite	Na₂Ca₂(V₁₀O₂₈) · 24H₂O	Tric. 1 : P1
4.HC.45	Nashite	Na₃Ca₂[(V⁵⁺₉V⁴⁺)O₂₈] · 24H₂O	Mon. 2/m : P2₁/m
4.HC.50	Okieite	Mg₃[V₁₀O₂₈] · 28H₂O	Tric. 1 : P1
4.HC.55	Postite	Mg(H₂O)₆Al₂(OH)₂(H₂O)₈(V₁₀O₂₈) · 13H₂O	Orth. mmm (2/m 2/m 2/m) : Pccn
4.HC.60	Schindlerite	{(NH₄)₄Na₂(H₂O)₁₀}{V₁₀O₂₈}	Tric. 1 : P1

Fluorescence of ProtocaseyiteHide

In UV light:

None

Other InformationHide

Notes:

Insoluble in water, soluble in dilute HCl.

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 ProtocaseyiteHide

mindat.org URL:

https://www.mindat.org/min-55381.html
Please feel free to link to this page.

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External Links:

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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 ProtocaseyiteHide

Reference List:

Miyawaki, Ritsuro, Hatert, Frédéric, Pasero, Marco, Mills, Stuart J. (2021) IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) CNMNC Newsletter No 60. Mineralogical Magazine, 1-5 doi:10.1180/mgm.2021.30

Kampf, Anthony R., Cooper, Mark A., Hughes, John M., Ma, Chi, Casey, William H., Hawthorne, Frank C., Marty, Joe (2022) Protocaseyite, a new decavanadate mineral containing a [Al₄(OH)₆(H₂O)₁₂]⁶⁺ linear tetramer, a novel isopolycation. American Mineralogist, 107 (6) 1181-1189 doi:10.2138/am-2022-8059

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

Localities for ProtocaseyiteHide

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.

USA (TL)

Colorado

San Miguel County

Slick Rock Mining District

ⓘ Burro Mine (TL)

Mineralogical Magazine: 85 +2 other references

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Protocaseyite