tonstein

== English == === Etymology === Borrowed from German Tonstein, from Ton (“clay”) + Stein (“stone”). === Pronunciation === enPR: tŭn′stīn′ (Received Pronunciation, General American, Canada, Scotland) IPA(key): /ˈtʌnˌstaɪ̯n/ (Canada) IPA(key): /ˈtʌnˌstʌɪ̯n/ (Scotland) IPA(key): /ˈtʌnˌstʌi̯n/, /ˈtʌnˌstəi̯n/ (General Australian) IPA(key): /ˈtɐnˌstɑe̯n/ (New Zealand) IPA(key): /ˈtɐnˌstaɪ̯n/ (India) IPA(key): /ˈʈənˌsʈajn/ Rhymes: -aɪn Hyphenation: ton‧stein === Noun === tonstein (countable and uncountable, plural tonsteins) (geology) A hard, compact, kaolinite-rich claystone formed by the diagenetic alteration of volcanic ash, usually occurring as thin, laterally persistent layers interbedded with coal seams. (petrology) Any indurated argillaceous rock that stands out within coal measures as a distinctive marker horizon. ==== See also ==== bentonite claystone fireclay seat earth shale tuff