iddingsiteEnglishOxford Dictionary of Englishiddingsite /ˈɪdɪŋzʌɪt / ▸ noun [mass noun] a brownish mineral deposit consisting of a mixture of silicates, formed by alteration of olivine. – ORIGIN late 19th century: from the name of Joseph P. Iddings (1857–1920), American geologist, + -ite1.