ottrélite

{{Infobox mineral | name = Ottrelite | boxwidth = | boxbgcolor = | image = Ottrelite-41820.jpg | imagesize = | alt = | caption = Ottrelite | category = Nesosilicate | formula = | strunz = 09.AF.85 | symmetry = | unit cell = | molweight = 490.11 | colour = | color = Pistachio green | habit = Granular | system = | twinning = Polysynthetic, {001} | cleavage = {001} perfect; {110} likely | fracture = | tenacity = | mohs = 6–7 | luster = Vitreous to nearly adamantine on cleavages | streak = Greenish, grayish | diaphaneity = Translucent | gravity = 3.50 | density = 3.52 | polish = | opticalprop = | refractive = | birefringence = | pleochroism = | 2V = | dispersion = r > v, strong | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | prop1 = | prop1text = | references = }}

Ottrelite is a form of chloritoid. Its empirical formula is .