The grouplet is named "pyroxene pallasites" because they or the only pallasites that contain pyroxene. The grouplet was proposed in 1995. It currently has only 2 members: the Vermillion and Yamato 8451 meteorite. Both meteorites contain pyroxene and have a number of other similarities: for example their pyroxene composition, rare earth element concentrations, and oxygen isotope ratios. However, there are also indicators against the grouping of these two meteorites: for example the texture and occurrence of cohenite in the Vermillion meteorite and the differing siderophile trace element concentrations.
^ abBoesenberg, Joseph S.; Davis, Andrew M.; Prinz, Martin; Weisberg, Michael K.; Clayton, Robert N.; Mayeda, Toshiko K. (1 July 2000). "The pyroxene pallasites, Vermillion and Yamato 8451: Not quite a couple". Meteoritics & Planetary Science35 (4): 757–769. doi:10.1111/j.1945-5100.2000.tb01460.x.