Comendite

{{short description|Hard, peralkaline igneous rock, a type of light blue grey rhyolite}} thumb|Comendite at Lookout 589 in the Glass House Mountains '''Comendite''' is a hard, peralkaline igneous rock, a type of light blue grey rhyolite.<ref>{{Cite journal|last1=Troll|first1=Valentin R.|last2=Schmincke|first2=Hans-Ulrich|date=2002-02-01|title=Magma Mixing and Crustal Recycling Recorded in Ternary Feldspar from Compositionally Zoned Peralkaline Ignimbrite 'A', Gran Canaria, Canary Islands|url=https://academic.oup.com/petrology/article/43/2/243/1550415|journal=Journal of Petrology|language=en|volume=43|issue=2|pages=243–270|doi=10.1093/petrology/43.2.243|issn=0022-3530|doi-access=free}}</ref> Phenocrysts are sodic sanidine with minor albite and bipyramidal quartz.<ref name=Iddings>Iddings, Joseph Paxson, 1913, ''Igneous rocks: composition, texture and classification'', v. 2, pp. 94-96</ref> The blue colour is caused by very small crystals of riebeckite or arfvedsonite.<ref>Rocks and landscapes of the Sunshine Coast by Warwick Willmott, Brisbane: Geological Society of Australia Queensland Division, 2007</ref> The 1903 eruption of Changbaishan volcano in northeast China erupted comendite pumice.<ref>[http://www.volcanodiscovery.com/changbaishan.html Changbaishan volcano, China - facts and information]. Retrieved 2013-07-24.</ref>

Comendite derives its name from the area of Le Commende on San Pietro Island in Italy, where the rock type is found.<ref>Cioni, R. and Funedda, A., (2005) ''Structural geology of crystal-rich, silicic lava flows: A case study from San Pietro Island (Sardinia, Italy)'' in Manga, M. and Ventura, G. (editors) (2005) ''Kinematics and Dynamics of Lava Flows'', Geological Society of America Special Paper 396, pages 1 to 14.</ref> Comendite also occurs in the Glass House Mountains of southeast Queensland, Australia, as well as in Sardinia, Corsica, Ascension Island, Ethiopia, Somalia and other areas of East Africa.<ref name=Iddings/>

==References== {{Reflist}}

Category:Rhyolite