alumocalcite
/əˌl(j)uːmə(ʊ)ˈkalsʌɪt/Mineralogy. Now rare
noun
A variety of opal containing lime and alumina as impurities.
Origin
Mid 19th century; earliest use found in Charles Shepard (1804–1886). From German Alumocalcit (A. Breithaupt Vollständige Charakteristik des Mineral-Syst. (ed. 3, 1832) 97; from alum- (in †Alumina) + -o- + classical Latin calc-, calx lime + German -it), with remodelling of the ending after words in -ite.