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Formula: Zn2(PO4)(OH)
Anhydrous phosphate containing hydroxyl
Crystal System: Triclinic
Specific gravity: 4.12 measured, 4.19 calculated
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 zinc-bearing ore deposits
(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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