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A gabbro composed principally of calcic plagioclase and olivine. Also known as forellenstein.



an igneous rock of the gabbro group, consisting mainly of basic plagioclase (labradorite or bytownite) and small amounts of olivine. Pyroxenes are either present in negligible amounts or completely absent. Serpentinization of the olivine is sometimes accompanied by the formation of characteristic fissures, which radiate from the olivine grains, in the plagioclase.

References in periodicals archive ?
Dighem airborne geophysical data suggests that the main mineralised troctolite body continues west of grid line 0 + 00 for approximately an additional 5 km.
Occurrences of major mafic-ultramafic bodies in the northern Dashwoods Subzone # (a) Location Lithology Mineralogy (b) 1 Puddle Pond Troctolite, ol-gabbro, Varying amounts of gabbro, hbl gabbro, Ol+Pl+Cpx+Hbl+Opx+/-Bt# ol-norite 2 John's Brook Gabbro, hbl-gabbro Cpx+Pl+Hbl# Lake gabbro 3 Whaleback Lherzolite, dunite, Relic Ol+Cpx+opx; Pond websterite, wehrlite, Tr+Chl+Srp+Car; Hbl+Pl# metagabbro 4 W of Silver Dunite, wehrlite, Relic O1+Cpx+Opx+Cr; Pond harzburgite, Tr+Chl+Srp+Car; Am+Chl pyroxenite, gabbro.
Stephen est constitue d'un noyau de dunite et de troctolite, entoure de strates de gabbro et de gabbro a olivine.
Stephen Gabbro consists of complexly intermingled olivine gabbro, olivine gabbronorite, and olivine norite, with less abundant gabbro, gabbronorite, norite, troctolite, anorthosite, and dunite.