Limburgite

In petrology, limburgite is a dark-colored volcanic rock resembling basalt in appearance, but containing normally no feldspar.

Within the groundmass a second generation of small euhedral augites frequently occurs; more rarely olivine is present also as an ingredient of the matrix.

Hauyne is an ingredient of some of the limburgites of the Cape Verde Islands.- Rocks of this group occur in considerable numbers in Germany (Rhine district) and in Bohemia, also in Scotland, Auvergne, Spain, Africa (Kilimanjaro) and Brazil.

From the last-named rocks the limburgites are not easily separated as the two classes bear a very close resemblance in structure and in mineral composition, though many authorities believe that the ground mass of the monchiquites is not a glass but crystalline analcite.

Closely allied to them are the augitites, which are distinguished only by the absence of olivine; examples are known from Bohemia, Auvergne, the Canary Islands and Ireland.