The Lamproite Clan

Abstract

Igneous rock classifications have never been graced with the elegance and simplicity of terminology employed in other branches of science. Consequently rock names present us with a bewildering plethora of unrelated, noninformative, and commonly unpronounceable terms. This unfortunate and unsatisfactory situation resulted from the empirical approach to rock nomenclature developed in the nineteenth century coupled with active resistance by petrologists to objective classifications. Petrographers, using the then recently invented polarizing microscope, coined a new name for each newly recognized assemblage of minerals. Different names were also proposed for rocks that differed only in the modal proportions of a particular mineral assemblage. The name was usually derived from the geographic locality at which the rock was discovered. Commonly, as a consequence of poor communication, different names were applied to rocks consisting of the same mineral assemblages.

The trouble is not with classification but with nature which did not make things right.

Albert Johannsen (1931)