Cadwaladerite (original) (raw)

A valid IMA mineral species - grandfathered

About CadwaladeriteHide

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Formula:

Al5(H2O)3(OH)12 · n(Cl,H2O)

Name:

Named in honor of Charles Meigs Biddle Cadwalader (3 June 1885, Fort Washington, Pennsylvania, USA - 18 June 1959, Whitemarsh, Pennsylvania, USA), Managing Director and President of the Academy of Natural Sciences, Philadelphia, Pennsylvania, USA, between 1928 and 1951.

It was demonstrated that cadwaladerite and lesukite are the same mineral species. Because cadwaladerite has historical precedence, it is recognized as a valid mineral species, whereas lesukite is discredited (IMA proposal 18-H), see Peterson et al. (2019).

When the mineral is washed, Cl is lost from the crystal structure and the refractive index decreases (Peterson et al., 2019)

Unique IdentifiersHide

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Long-form identifier:

mindat:1:1:845:1

ec15e89a-20ac-45eb-a69d-82706525dbcf

IMA Classification of CadwaladeriteHide

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Approved, 'Grandfathered' (first described prior to 1959)

IMA status notes:

Redefined by the IMA

IMA Formula:

Al2(OH)5Cl · 2H2O

Approval history:

2019: Redefined by IMA Al5(H2O)3(OH)12·n(Cl,H2O) (IMA proposal 18-H).

Classification of CadwaladeriteHide

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3.BD.05

3 : HALIDES
B : Simple halides, with H2O
D : Simple halides with H2O and additional OH

10.5.1.1

10 : OXYHALIDES AND HYDROXYHALIDES
5 : Am(O,OH)pXq

8.6.3

8 : Halides - Fluorides, Chlorides, Bromides and Iodides; also Fluoborates and Fluosilicates
6 : Halides of Al

Mineral SymbolsHide

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

Physical Properties of CadwaladeriteHide

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Density:

1.66 g/cm3 (Measured)

Optical Data of CadwaladeriteHide

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RI values:

_n_α = 1.511 - 1.563

Birefringence:

Isotropic minerals have no birefringence

Comments:

Refractive index depends on Cl content (washing decreases Cl content).

Chemistry of CadwaladeriteHide

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Mindat Formula:

Al5(H2O)3(OH)12 · n(Cl,H2O)

Crystallography of CadwaladeriteHide

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Class (H-M):

23 - Tetartoidal

Cell Parameters:

a = 19.840(12) Å

Unit Cell V:

7,809.53 ų (Calculated from Unit Cell)

Morphology:

Amorphous grains and small masses. Tiny cubic crystals.

Comment:

Formerly assumed to be amorphous. Space group and unit cell from Peterson et al. (2019). Range of unit-cell parameter a: 19.788 to 19.859 Å.

X-Ray Powder DiffractionHide

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Powder Diffraction Data:

Comments:

Type material #134143 (Peterson et al. 2019).

Geological EnvironmentHide

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Geological Setting:

Evaporitic, coal fires, fumaroles.

Type Occurrence of CadwaladeriteHide

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General Appearance of Type Material:

Grains and small masses in halite.

Place of Conservation of Type Material:

Harvard University, Cambridge, Massachusetts,, USA, number 134143.

Geological Setting of Type Material:

Complex of small sulfate outcrops, at the edge of an evaporite basin.

Associated Minerals at Type Locality:

Synonyms of CadwaladeriteHide

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Other Language Names for CadwaladeriteHide

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Common AssociatesHide

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Associated Minerals Based on Photo Data:

Related Minerals - Strunz-mindat GroupingHide

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Other InformationHide

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Notes:

Weakly hygroscopic.

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 CadwaladeriteHide

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References for CadwaladeriteHide

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Reference List:

**Palache, Charles, Berman, Harry, Frondel, Clifford (1951) The System of Mineralogy (7th ed.) Vol. 2 - Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Ect. John Wiley and Sons, New York.**p.77

Vergasova, L.P., Stepanova, E.L. Serafimova, E.K., Filatov, S.K. (1997) Lesukite, Al2(OH)5Cl·2H2O — a new mineral from volcanic exhalations. Zapiski Vserossiyskogo Mineralogicheskogo Obshchestva (Proceedings of the Russian Mineralogical Society), 126(2), 104–110. (in Russian, as lesukite)

Peterson, R.C., Metcalf, M., Kampf, A.R., Contreira Filho, R.R., Reid, J., Joy, B. (2019) Cadwaladerite, Al2(H2O)(OH)4·n(Cl,OH-,H2O), from Cerros Pintados, Chile, defined as a valid mineral species and the discreditation of lesukite. The Canadian Mineralogist: 57: 827-841.

Localities for CadwaladeriteHide

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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

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- 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.