Among the names of stones in the Alfonsine lapidaries are a number, frequently recurring, which are given in the manuscript as Chaldean names, and are usually followed by their equivalents or definitions in Spanish. Some thirty-seven of these have been listed by M. F. de Mély, who expresses the hope that someone will undertake the task of defining and identifying them. Thus far, however, no one has made any thoroughgoing attempt to investigate these Chaldean stone-names. The only identifications made by Mély himself are the names catu and alfeyru (alfeyxu), feynac. A single identification of bezebekaury as ruby is made by Barrington, who, as others have done, has pointed out the difficulty of identifying these Alfonsine stones. Before undertaking this task it will be necessary to correct and complete the list given by Mély, which really comprises 36 instead of 37 names since one stone is twice counted. Actually, the manuscript mentions no less than forty-five Chaldean stones.