Naldrettite

Naldrettite is a mineral with a chemical formula of Pd2Sb. It is named after Anthony J. Naldrett (born 1933), a professor at the University of Toronto, who has made significant contributions to the International Mineralogical Association (IMA). Naldrettite is a new intermetallic mineral from the Mesamax Northwest deposit, Ungava region, Québec, Canada. Mineralization takes place around the base of basaltic dyke margins. Naldrettite is economically important because of its chemical composition (Pd2Sb). The sample in which the new mineral was discovered had high platinum group elements (PGEs) with palladium enrichment.[1]

Naldrettite
General
CategorySulfide mineral
Formula
(repeating unit)		Pd2Sb
Strunz classification2.AC.25d
Crystal systemOrthorhombic
Crystal classDipyramidal (mmm)
H-M Symbol: (2/m 2/m 2/m)
Space groupCmc21
Unit cella = 3.3906(1), b = 17.5551(5)
c = 6.957(2) [Å]; Z = 8
Identification
ColorAppears creamy white in plane-polarized light
Twinningstrain-induced polysynthetic
FractureIrregular
TenacityDuctile, Flexibly inelastic
Mohs scale hardness4-5
Lustermetallic
Diaphaneityopaque
Density10.694(1) g/cm3
Refractive indexin oil 1.515
Pleochroismnon-pleochroic
Melting point580 °C
References[1]

Naldrettite occurs as anhedral grains that are commonly attached to sulfide minerals and are associated with clinochlore. It belongs to the orthorhombic crystal system and is a part of the pyramidal class.[1] This means that all of the edge lengths (a,b,c) of the unit cell are different in length and intersect at right angles to each other. The mineral is metallic, opaque, appears bright creamy white under plane polarized light, has weak bireflectance, and does not exhibit internal reflections.[2]

References
  1. Cabri,L.J., McDonald,A. M., Stanley, C. J., Rudashevsky, N. S., Poirier,G. Durham, B. R., Mungall, J. E., and Rudashevsky, V. N. (2005), Naldrettite, Mineralogical Magazine, 69, 89-97.
  2. Mindat.org Accessed 28 October 2010
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