Limburgite is a dark or darkish volcanic rock similar to basalt but containing no feldspars. It is named after its type locality, the 'Limburg', a locality along the river Rhine in southwest Germany. Limburgite has a porphyritic texture and is essentially consists of alkaline minerals such as olivine, augite. The dark amorphous groundmass of the rock is interspersed with full grown crystals of augite and other pyroxenes as well as small cavities lined with microcrystalline alkaline minerals like zeolite. Width of sample is 120 mm.