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Mineralpedia Details for Kidwellite

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Kidwellite

Kidwellite

Named after Albert Laws Kidwell of Texas, USA for his contributions to the knowledge of Arkansas phosphate deposits. Kidwellite is an uncommon mineral that can be found as a replacement for early phosphate minerals. It occurs in localities in the United States, Germany, England, Australia, and Namibia, among a few others.

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/kidwellite.pdf

Formula
NaFe3+9(PO4)6(OH)11ยท3H2
Crystal System
Monoclinic 
Crystal Habit
Fibrous, Columnar 
Cleavage
Perfect, None, None 
Luster
Silky 
Color
greenish yellow, greenish white, yellow, light green 
Streak
yellow 
Class
Monoclinic - Prismatic 
Hardness
WebMineral
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Mindat
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Kidwellite from Coon Creek, Polk Co., Arkansas, United States

Kidwellite
            from Coon Creek, Polk Co., Arkansas, United States

Compact radial and concentric groups to 8mm across of yellowish green to dark green Kidwellite in matrix.

Dark green radial and concentric crystal aggregates to 5mm across.

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Kidwellite from Silver Coin mine, Humboldt Co., Nevada, United States

Kidwellite
            from Silver Coin mine, Humboldt Co., Nevada, United States

Tiny grass green crude spheroidal crystals to about 0.5mm.

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Kidwellite from Three Oaks Gap, Polk Co., Arkansas, United States

Kidwellite
            from Three Oaks Gap, Polk Co., Arkansas, United States

Grass green spherulitic groups of Kidwellite lining a large 5x3cm vug rimmed by dark red Beraunite.

Little green Kidwellite balls, less than 0.3mm, which appear to float on Cacoxenite sprays much like ice cream cones. 

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Kidwellite from Fodderstack Mountain, Montgomery Co., Arkansas, United States

Kidwellite
            from Fodderstack Mountain, Montgomery Co., Arkansas, United States
Special Info
Type Locality

This is not just another Kidwellite. These crystals are distinct and are not the usual mammilary crusts. The crystal groups are composed of radiating acicular crystals easily visible.

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Kidwellite from Indian Mountain, Cherokee Co., Alabama, United States

Kidwellite
            from Indian Mountain, Cherokee Co., Alabama, United States
Special Info
Specimen and Photo by: Henry Barwood Professor, Earth Science Department of Chemistry and Physics

Tiny crystals of Kidwellite from the old locality on Indian Mountain north of the extinct town of Bluffton, Cherokee County, Alabama. Early collecting produced a few thin veins with these little crystals of kidwellite. Identified them using powder XRD. FOV is about .6  X .5mm.

Imaged with a Canon 40D, 23mm Nikon objective and 300mm Canon FD telephoto in a tube configuration and stacked using Combine Z software.

 

 

Henry Barwood
Professor, Earth Science
Department of Chemistry and Physics
Troy University
Troy, Alabama 36082

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Kidwellite from York mine, Polk Co., Arkansas, United States

Kidwellite
            from York mine, Polk Co., Arkansas, United States

 They called this mineral "Laubmannite" at one time from the Coon Creek area.

A superb botryoidal specimen of velvety light green Kidwellite. On the sides are nice concentric patterns of Kidwellite with other phosphates.

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