The Lapidario [Lapidary] is a compendium of four treatises analysing different types of stones and their uses and properties in connection with the influence of the stars.
The codex is notable for its magnificent visual repertoire, especially the first treatise, which contains illustrations of the discovery of stones and the constellations that influence their properties. The work also deals with medicinal matters, as it describes the curative uses of stones, as well as alchemical aspects. However, the idea that stones receive their properties from the stars, through God and his angels, is stressed throughout the manuscript.
This is the first scientific work promoted by Alfonso X. According to the prologue, the original in Arabic was located in Toledo, where it found its way into the monarch’s hands. The king decided to have it translated into Spanish on the advice of Yehudá ben Mošé, a Jewish scientist in his service. The translation was carried out from 1243 to 1250, under the supervision of Yehudá and cleric Garcí Pérez. New content was then progressively added until the final text copied in the manuscript housed in the Royal Library of the Monastery of El Escorial was completed around 1270−75.