Editing Kimberlite (section)

=== Olivine lamproites ===

Olivine lamproites were previously called group II kimberlite or orangeite in response to the mistaken belief that they only occurred in South Africa. Their occurrence and petrology, however, are identical globally and should not be erroneously referred to as kimberlite.<ref>{{cite journal |last1=Francis |first1=Don |last2=Patterson|first2=Michael|title=Kimberlites and aillikites as probes of the continental lithospheric mantle|journal=Lithos|date=April 2009|volume=109|issue=1–2|pages=72–80 |doi= 10.1016/j.lithos.2008.05.007|bibcode=2009Litho.109...72F }}</ref> Olivine lamproites are [[ultrapotassic igneous rocks|ultrapotassic]], [[peralkaline rock]]s rich in volatiles (dominantly H<sub>2</sub>O). The distinctive characteristic of olivine lamproites is [[phlogopite]] macrocrysts and microphenocrysts, together with groundmass micas that vary in composition from phlogopite to "tetraferriphlogopite" (anomalously Al-poor phlogopite requiring Fe to enter the tetrahedral site). Resorbed olivine macrocrysts and euhedral primary crystals of groundmass olivine are common but not essential constituents.

Characteristic primary phases in the groundmass include zoned pyroxenes (cores of diopside rimmed by Ti-aegirine), spinel-group minerals (magnesian [[chromite]] to titaniferous [[magnetite]]), Sr- and [[Rare-earth element|REE]]-rich [[perovskite]], Sr-rich [[apatite]], REE-rich phosphates ([[monazite]], daqingshanite), potassian barian [[hollandite]] group minerals, Nb-bearing [[rutile]] and Mn-bearing [[ilmenite]].