Tarbuttite

phosphate

Formula: Zn2(PO4)(OH)
Anhydrous phosphate containing hydroxyl
Specific gravity: 4.12
Hardness: 3½
Streak: White
Colour: White, colourless, yellow, red green or brown; colourless in transmitted light.
Environments

Pegmatites (in France)
Hydrothermal environments

Tarbuttite is a rare secondary zinc phosphate occurring in the oxidised portions of Zn-bearing ore deposite (Webmin, Mindat, HOM). It may form pseudomorphs after smithsonite, descloizite, hemimorphite and hopeite (R&M 94.2.139-142), and it may alter to parahopeite (Mindat). Associated minerals include smithsonite, descloizite, hemimorphite, hopeite, parahopeite, hydrozincite, scholzite, cerussite, pyromorphite, vanadinite and limonite (HOM).

At Reaphook Hill, South Australia, tarbuttite is associated with scholzite (R&M 94.2.154) and hillite (MinRec 35.4.352).

In France, three pegmatite-hosted tarbuttite localities have been reported (R&M 94.2.154).

At the Type Locality, the Kabwe Mine, Central Province, Zambia, tarbuttite is abundant, occurring in the upper portion of the oxidation zone where phosphatic solutions reacted with earlier formed hemimorphite and cerussite (Mindat). It is found on goethite and often associated with descloizite, smithsonite or pyromorphite. On the surfaces of the tarbuttite crystals occasionally there are rosettes of minute hemimorphite crystals. It may form pseudomorphs after smithsonite, descloizite, hemimorphite and hopeite (R&M 94.2.139-142). Epimorphic coatings of hydroxylapatite on tarbuttite have also been found (R&M 94.2.151-152). Other associated minerals include vanadinite, pyromorphite, goethite, hydrozincite and cerussite (Mindat, Dana R&M 94.2.150-153).

At the Skorpion mine, Namibia, tarbuttite is associated with hetaerolite, hydrozincite, skorpionite, smithsonite, hemimorphite and scholzite. The hydrozincite occurs as coatings on tarbuttite, as do hemimorphite and stolzite, occasionally (R&M 94.2.151-152). Fluorapatite has also been found partially replacing tarbuttite (MinRec 41.6.547).

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