polymignite
/ˌpɒlɪˈmɪɡnʌɪt/Mineralogy. Now rare
noun
A mineral occurring as prismatic black crystals that is a metamict oxide of calcium, zirconium, and several other metals and has been regarded as a variety of zirconolite.
Origin
Early 19th century; earliest use found in Annals of Philosophy. From Swedish polymignit from poly- + ancient Greek μιγνύναι to mix + Swedish -it.