During the winter of 1921 the writer collected in the Wet Weather Quarry of the Riverside Portland Cement Company, at Crestmore near Riverside, California, a number of specimens of an unusual pegmatite. The pegmatite vein itself could not be located in the quarry face but the blocks on the quarry floor carried pegmatite cutting across limestone as well as contact rock. The veins were made up largely of feldspar with wollastonite, orange colored prehnite and massive greenish datolite. The quartz of the pegmatite was wholly or in part replaced by a mineral that proved to be identical with the mineral centrallasite. This occurrence is, therefore, a second locality for this mineral. Excellent material was obtained for a determination of its chemical and physical properties. These show conclusively that centrallasite is distinct from any other mineral and should, therefore, be raised to the rank of a species.