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Tarbuttite  
Current inventory:  0 gems
 

  
Tarbuttite was named to honor Percy Coventry Tarbutt, Director of the Broken Hill Exploration Company, who collected some of the first specimens at Broken Hill (now Kabwe), Zambia.

Discovered in 1907.  IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

Zn₂(PO₄)(OH)

Zinc Phosphate Hydroxide

Molecular Weight:

242.76 gm

Composition:

Zinc

53.87 %

Zn

67.05 %

ZnO

Phosphorus

12.76 %

P

29.24 %

P₂O₅

Hydrogen

0.42 %

H

3.71 %

H₂O

Oxygen

32.95 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Phosphates

Strunz 8th Ed. ID:

7/B.06-50

Nickel-Strunz 10th Ed. ID:

8.BB.35

8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H₂O
B : With only medium-sized cations, (OH, etc.):RO₄ about 1:1

Related to:

Olivenite Group. Tarbuttite Group. May form pseudomorphs after Smithsonite, Descloizite and possibly also Hemimorphite. May alter to Parahopeite.

Crystal Data

Crystallography:

Triclinic - Pinacoidal

Crystal Habit:

Crystals typically equant to short prismatic, complex, with many forms, to 2 cm; in sheaflike or saddle-shaped aggregates; as crusts.

Twinning:

None

Physical Properties

Cleavage:

Perfect on {001}

Fracture:

Uneven/Irregular

Tenacity:

Brittle

Moh's Hardness:

3.5 - 4.0

Density:

4.12 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Optical Properties

Color:

Colorless, pale yellow, may be brown, red, or green; colorless in transmitted light.

Transparency:

Translucent to Transparent

Luster:

Vitreous, Pearly on cleavages

Refractive Index:

1.659 - 1.713  Biaxial ( - )

Birefringence:

0.0530

Dispersion:

Weak to Strong

Pleochroism:

Very Strong

Occurances

Geological Setting:

An uncommon secondary mineral in the oxidized zone of zinc-bearing deposits.

Common Associations:

Hopeite, Hemimorphite, Smithsonite, Parahopeite, Hydrozincite, Scholzite, Cerussite, Pyromorphite, Descloizite, Vanadinite, “Limonite”

Type Locality:

Kabwe Mine (Broken Hill Mine), Kabwe (Broken Hill), Central Province, Zambia

Year Discovered:

1907

View mineral photos:

Tarbuttite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Tarbuttite is a rare zinc phosphate mineral that belongs to the Olivenite Group of minerals that also includes Adamite. Tarbuttite is typically rather unattractive, even ugly by mineral specimen standards. It has been referred to as a bat-poop mineral since it often forms in ancient caves under layers of mineral-rich bat guano deposited over tens of thousands of years. However, specimens from the Skorpion Mine in the Rosh Pinah, Lüderitz District, Karas Region of Namibia are different. Crystals from a new find there in 2007 are transparent, pastel green and gemmy.

Tarbuttite has been found at these localities: the type locality at Kabwe (Broken Hill), Zambia. In the Lueca vanadium mines, Angola. From the Kef Semmah mine, near Sétif, Algeria. In Australia, on Reaphook Hill, near Blinman, Flinders Ranges, South Australia; at Broken Hill, New South Wales. In the Hudson Bay mine, Salmo, British Columbia, Canada. At an undefined locality in Guangdong Province, China. The best crystals are from the Skorpion Mine, Rosh Pinah, Lüderitz District, Karas Region, Namibia.
 

  
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