Editing Tourmaline (section)

== Geology ==
[[File:Tourmaline ore (1).webm|thumb|right|Video of tourmaline ore]]
Tourmaline is found in [[granite]] and granite [[pegmatite]]s and in [[metamorphic rock|metamorphic]] rocks such as [[schist]] and [[marble]]. Schorl and lithium-rich tourmalines are usually found in granite and granite pegmatite. Magnesium-rich tourmalines, dravites, are generally restricted to schists and marble. Tourmaline is a durable mineral and can be found in minor amounts as grains in [[sandstone]] and [[conglomerate (geology)|conglomerate]], and is part of the [[ZTR index]] for highly weathered sediments.<ref>{{Cite journal|last=Hubert|first=John F.|date=1962-09-01|title=A zircon-tourmaline-rutile maturity index and the interdependence of the composition of heavy mineral assemblages with the gross composition and texture of sandstones|url=https://pubs.geoscienceworld.org/sepm/jsedres/article-abstract/32/3/440/95590/a-zircon-tourmaline-rutile-maturity-index-and-the?redirectedFrom=fulltext|journal=Journal of Sedimentary Research|volume=32|issue=3|doi=10.1306/74D70CE5-2B21-11D7-8648000102C1865D| issn=1527-1404| url-status= live| archive-url= https://web.archive.org/web/20180104073105/https://pubs.geoscienceworld.org/sepm/jsedres/article-abstract/32/3/440/95590/a-zircon-tourmaline-rutile-maturity-index-and-the?redirectedFrom=fulltext|archive-date=2018-01-04}}</ref>