caryopilite

{{Infobox mineral | name = Caryopilite | category = Phyllosilicate minerals | group = Kaolinite-Serpentine group, serpentine subgroup | boxwidth = | boxbgcolor = | image = Caryopilite-Rhodochrosite-89634.jpg | imagesize = 260px | caption = Brown crust of caryopilite on rhodochrosite | formula = (Mn2+,Mg)3Si2O5(OH)4 | IMAsymbol=Cpl | strunz = 9.ED.15 | dana = 71.1.2b.1 | system = Monoclinic | class = Domatic (m) (same H-M symbol) | symmetry = Cm | unit cell = a = 5.66 Å, b = 9.81 Å, c = 7.52 Å, β = 104.52°; Z = 2 | molweight = 3 to 3.5 | color = Reddish brown, tanLight brown to yellow in thin section | habit = | twinning = | cleavage = Perfect on {001} | fracture = | tenacity = | mohs = | luster = Vitreous | polish = | refractive = nα = 1.606 to 1.620nβ = 1.632 to 1.650nγ = 1.632 to 1.650 | opticalprop = Biaxial (-) | birefringence = δ = 0.026 to 0.030 | 2V = ~0° | dispersion = Weak | pleochroism = | fluorescence= | absorption = | streak = Light Brown | gravity = | density = 2.83–2.94 (measured) | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = Semitransparent | other = | references = }}

Caryopilite (synonymous with ectropite and ektropite) is a brown-colored mineral with formula (Mn2+,Mg)3Si2O5(OH)4. The mineral was discovered in 1889 from a mine in Sweden. It was named for the Greek words for walnut and felt in reference to its appearance.