The rock is a dark-green peridotite (kimberlite) composed of serpentinized olivine and a number of accessory minerals, including phlogopite, pyrope, calcite, enstatite, magnesian ilmenite, and others.
en.wikipedia.org More generally, it refers to the dark mica series, primarily a solid-solution series between the iron-endmember annite, and the magnesium-endmember phlogopite; more aluminous endmembers include siderophyllite.
en.wikipedia.org Phlogopite and/or potassic amphibole probably are typical in the sources from which many such magmas have been derived.
en.wikipedia.org In some cases the phlogopite is considered to be produced by autogenic alteration during cooling.
en.wikipedia.org For example, the biotite series is represented by variable amounts of the endmembers phlogopite, siderophyllite, annite, and eastonite.
en.wikipedia.org