oncosine
/ˈɒŋkə(ʊ)siːn/(also onkosine) Mineralogy. Now historical
noun
An aluminosilicate of potassium, other alkali metals, and magnesium which is a variety of, or perhaps a mixture containing, muscovite.
Origin
Mid 19th century; earliest use found in James Dana (1813–1895), geologist, zoologist, and teacher. From German Onkosin from ancient Greek ὄγκωσις swelling, in allusion to its behaviour when heated in a blowpipe flame + German -in.