Editing Feldspathoid

{{short description|Mineral grouping of silica-poor tectosilicates}}
The '''feldspathoids''' are a group of [[Silicate minerals#Tectosilicates|tectosilicate]] [[mineral]]s which resemble [[feldspar]]s but have a different structure and much lower [[silica]] content. They occur in rare and unusual types of [[igneous rock]]s, and are usually not found in rocks containing primary quartz. A notable exception where feldspathoids and quartz-bearing rocks are found together is the [[Red Hill Syenite]].<ref>{{cite web |url=http://www.galleries.com/minerals/silicate/feldspat.htm |title=The Feldspathoid Group of Minerals |publisher=Amethyst Galleries, Inc. |website=Amethyst Galleries' Mineral Gallery |access-date=6 Jul 2015}}</ref>

'''Foid''', a contraction of the term ''feldspathoid'', is applied to any igneous rock containing up to 60% modal feldspathoid minerals. For example, a [[syenite]] with significant [[nepheline]] present can be termed a ''nepheline-bearing syenite'' or ''nepheline syenite'', with the term ''nepheline'' replaceable by any foid mineral. Such terminology is used in the Streckeisen ([[QAPF diagram|QAPF]]) classification of igneous rocks.<ref>{{cite book |title=A Dictionary of Earth Sciences |first1=Ailsa |last1=Allaby |first2=Michael |last2=Allaby |publisher=[[Oxford University Press]] |year=1999}}</ref>

==Feldspathoid minerals==
*{{annotated link|Afghanite}}
*{{annotated link|Analcime}}
*{{annotated link|Cancrinite}}
*{{annotated link|Kalsilite}}
*{{annotated link|Leucite}}
*{{annotated link|Nepheline}}
*Sodalite Group
**{{annotated link|Hauyne}}
**{{annotated link|Lazurite}}
**{{annotated link|Nosean}}
**{{annotated link|Sodalite}}
**{{annotated link|Tugtupite}}

==References==
{{Reflist}}

[[Category:Feldspathoid| ]]
[[Category:Tectosilicates]]


{{silicate-mineral-stub}}