labradoriteEnglishOxford New American Dictionarylabradorite /ˈlabrədôˌrīt, ˈlæbrədɔˌraɪt / ▸ noun a mineral of the plagioclase feldspar group, found in many igneous rocks. – ORIGIN early 19th century : from Labrador Peninsula, where it was found, + -ite1.