népouite

{{Infobox mineral | name = Népouite | category = Phyllosilicate minerals | group = Kaolinite-Serpentine group, serpentine subgroup | boxwidth = | image = Népouite MHNT.MIN.2005.0.63.jpg | imagesize = 260px | caption = Népouite from the Népoui Mine, North Province, New Caledonia. Specimen size: 21 cm. | formula = | IMAsymbol = Npo | molweight = | strunz = 9.ED.15 | dana = 71.1.2b.3 | system = Orthorhombic | class = pyramidal (mm2) (same H-M symbol) | symmetry = Ccm21 (no. 36) | color = bright green (typical of nickel bearing silicates) to yellowish or brownish green, depending on nickel content | habit = generally massive, also fibrous and microscopic pseudohexagonal platy crystals | cleavage = perfect on {001} | mohs = 2 to | luster = earthy to waxy, also pearly | streak = greenish white | diaphaneity = semitranslucent | gravity = 3.18 to 3.24 (measured) | density = | opticalprop = biaxial (−) | refractive = nα = 1.600 – 1.630 nγ = 1.635 – 1.650 | birefringence = 0.035 | pleochroism = weak. X = green to yellow green Z = yellow-green | 2V = | dispersion = | references = }}

Népouite is a rare nickel silicate mineral which has the apple green color typical of such compounds. It was named by the French mining engineer Edouard Glasser in 1907 after the place where it was first described (the type locality), the Népoui Mine, , Poya Commune, North Province, New Caledonia. The ideal formula is , but most specimens contain some magnesium, and is more realistic. There is a similar mineral called lizardite (named after the Lizard Complex in Cornwall, England) in which all of the nickel is replaced by magnesium, formula . These two minerals form a series; intermediate compositions are possible, with varying proportions of nickel to magnesium.