This important lapidary preserved at the Library of the royal site of Saint-Laurent-de-l'Escurial, richly illustrated and taken from Greek and Arabic sources, was translated from Arabic and perhaps augmented for Alfonso X of Castile by his medicine and astrologer Yehuda Mosca. It was originally, at least in its original form and if we are to believe the explanations in the first chapters, written in Syriac.

It contains a number of considerations on the magico-medical influence of stones in connection with astrology and as with Pliny, many of the references mentioned are not easy to identify. A compilation of four distinct treatises, the work offers as many stones as zodiacal degrees which are each associated with unique stars .