gatehouseite

{{Infobox mineral | name = Gatehouseite | category = Phosphate mineral | boxwidth = | boxbgcolor = | image =Gatehouseite.jpg | imagesize = |alt=Yellow crystals protrude from a dark-colored base| caption = | formula = Mn5(PO4)2(OH)4 | IMAsymbol = Ghs | molweight = | strunz = 8.BD.10 | dana = 41.4.1.2 | system = Orthorhombic | class = Disphenoidal (222) (same H-M symbol) | symmetry = P212121 | unit cell = a = 17.9733(18) Å b = 5.6916(11) Å c = 9.130(4) Å V = 933.9(4) Å3Z = 4 | color = Brownish orange to yellow | habit = | twinning = On {001}, contact twins | cleavage = Distinct on {010} | fracture = Splintery | tenacity = | mohs = 4 | luster = Adamantine | polish = | refractive = α = 1.74(1), β = n.d., γ = 1.76(1) | opticalprop = Biaxial (+/−) | birefringence = δ = 0.020 | 2V = | dispersion = | pleochroism = Distinct; brown to nearly colorless | fluorescence= | absorption = | streak = Pale yellow | gravity = | density = | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = Transparent | other = | references = }} Gatehouseite is a manganese hydroxy phosphate mineral with formula Mn5(PO4)2(OH)4. First discovered in 1987, it was identified as a new mineral species in 1992 and named for Bryan M. K. C. Gatehouse (born 1932). , it is known from only one mine in South Australia.

==Description== Gatehouseite occurs as radiating or divergent groups of bladelike crystals up to 100 μm by 20 μm by 5 μm in size and as overgrowths on arsenoclasite that are up to 5 mm long. The transparent mineral can be brownish-orange or yellow in color. Gatehouseite is the phosphorus analogue of arsenoclasite.