Wendwilsonite
Current inventory:  0 gems
 

  
Wendwilsonite was named in 1987 by Pete J. Dunn, Bozidar Darko Sturman, Joseph A. Nelen in honor of Dr. Wendell E. Wilson (1946 - ), editor and publisher of the Mineralogical Record for his contributions to specimen mineralogy.

Discovered in 1985; IMA status: Valid (IMA Approved 1985)

Chemistry

Chemical Formula:

Ca₂(Mg,Co)(AsO₄)₂ • 2H₂O; Often contains some Co replacing Mg.

Hydrated Calcium Magnesium Cobalt Arsenate

Molecular Weight:

426.99 gm

Composition:

Calcium

18.77 %

Ca

26.27 %

CaO

Magnesium

4.27 %

Mg

7.08 %

MgO

Cobalt

3.45 %

Co

4.39 %

CoO

Arsenic

35.09 %

As

53.83 %

As₂O₅

Hydrogen

0.94 %

H

8.44 %

H₂O

Oxygen

37.47 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Phosphates

Strunz 8th Ed. ID:

7/C.17-90

Nickel-Strunz 10th Ed. ID:

8.CG.10

8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H₂O
G : With large and medium-sized cations, RO₄:H₂O = 1:1

Related to:

Roselite Group, Roselite-Wendwilsonite Series. The magnesium (Mg) analogue of Roselite. Isostructural with Brandtite.

Members of Group:

Roselite Group: Brandtite, Kröhnkite, Roselite, Rruffite, Unnamed (Fe2+-analogue of Brandtite), Wendwilsonite, Zincroselite 

Varieties:

None

Synonyms:

IMA1985-047

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

Crystals are stout prismatic, elongated along [100], showing {011}, {111}, {010}, {110}, to 6 mm.

Twinning:

On {100} as twin and composition plane; lamellar structure || {010}, {011}, {111} visible optically. 

Physical Properties

Cleavage:

Perfect on {010} 

Fracture:

Irregular/Uneven

Tenacity:

Brittle

Moh's Hardness:

3.0 - 4.0

Density:

3.52 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Health Warning:

Contains arsenic - always wash hands after handling. Avoid inhaling dust when handling or breaking. Never lick or ingest.

Optical Properties

Color:

Pale to intense pink, may be red; commonly color zoned

Transparency:

Transparent, Translucent

Luster:

Vitreous

Refractive Index:

1.694 - 1.713  Biaxial ( + )

Birefringence:

0.019

Dispersion:

Weak to distinct; r < v

Pleochroism:

X = violet-pink; Y = rose-pink; Z = colorless

Occurances

Geological Setting:

A rare secondary mineral in cobalt-bearing hydrothermal mineral deposits.

Common Associations:

At Bou Azzer, Morocco: Talmessite, Erythrite. At Sterling Hill: Calcite, Serpentine, with very sparse Franklinite and Willemite.

Common Impurities:

n/a

Co-type Locality:

• (possibly Arhbar mine), Bou Azzer District, Tazenakht, Ouarzazate Province, Souss-Massa-Draâ Region, Morocco;
• Sterling Mine, Sterling Hill, Ogdensburg, Franklin Mining District, Sussex County, New Jersey, USA

Year Discovered:

1985

View mineral photos:

Wendwilsonite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Wendwilsonite was named in 1987 by Pete J. Dunn, Bozidar Darko Sturman, Joseph A. Nelen in honor of Dr. Wendell E. Wilson (1946 - ), editor and publisher of the Mineralogical Record magazine since 1976, for his contributions to specimen mineralogy. Wilson was also the recipient of the Carnegie Mineralogical Award for 2001. The Mineralogical Record magazine is highly respected, award-winning and is the premier journal for serious mineral collectors. In 1982, The Mineralogical Record magazine became the first (and is still the only) journal ever to be honored with the naming of a new mineral species (Minrecordite), and again in 1994, when it became the first (and is still the only) journal ever to win the prestigious Carnegie Mineralogical Award.

Wendwilsonite is a rare secondary mineral in cobalt-bearing hydrothermal mineral deposits and is the magnesium (Mg) analogue of Roselite. In early 1985 Pete J. Dunn of the Department of Mineral Sciences, Smithsonian Institution, Washington, D.C., U.S.A. examined a pink mineral from Sterling Hill, New Jersey. Analysis of the mineral showed it to be almost identical to Roselite. However, Roselite has a cobalt (Co)-dominant chemistry and the samples from Sterling Hill, New Jersey as well as from Coahuila, Mexico and many from Bou Azzer, Morocco, proved to be magnesium (Mg)-dominant, and thus represented a new mineral species and the creation of the Roselite-Wendwilsonite Series. Samples of Wendwilsonite from Bou Azzer, Morocco consist of pink glassy crystals, up to 6 mm in size, associated with Talmessite and Erythrite on altered ore and Calcite gangue. At Sterling Hill, Wendwilsonite forms 0.5-mm crystals with Calcite crystals on a serpentine, which encrusts manganoan Calcite with very sparse Franklinite and Willemite. Only a few specimens are known, thus rare at this locality.

Distribution: From Bou Azzer, Morocco. At Sterling Hill, Ogdensburg, Sussex County, New Jersey, USA. From an unknown locality in Coahuila, Mexico.
 

  
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