What is a pegmatoid in geology ?

Pegmatoid : definition

A pegmatoid (or pegmatitoid) is a pegmatite without quartz, with orthoclase and nepheline, related to the massifs of nepheline syenites or to the ultrabasic massifs. In the first case, the pegmatoids are rich in feldspars, aegirine, and rare-earth complex minerals (eudialyte, aeschynite, etc...), in the second case, in apatite, phlogopite and magnetite.

More generally, this term designates the coarse-grained differentiation facies of basaltic rocks. It represents, as in the case of granitic pegmatites, the product of final differentiation of basic magmas.

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