ottrelite
/ˈɒtrəlʌɪt/Mineralogy
noun
A hydroxide and aluminosilicate of magnesium, ferrous iron, and manganese which occurs as greyish to black crystalline scales.
- Sometimes considered to be a variety of chloritoid, ottrelite has been found to consist of monoclinic and triclinic polymorphs..
Origin
Mid 19th century (in an earlier sense). From Ottré (formerly also Ottrez), the name of a village in Belgium + -lite. In sense 1 after German Ottrelith.