Azhār al-Afkār fī Jawāhir al-Ahjār (The blossoms of thoughts regarding precious stones) is considered the most detailed and complete treatise of the Middle Ages on stones and their properties. Lapidaries, or treatises devoted entirely to the discussion of precious stones and their features, can be traced to ancient Greece. Pliny, in his Naturalis Historia (Natural history), mentions at least 20 authors as sources of his knowledge of stones, even though, of the works he cites, only the treatise On Stones by Theophrastus (circa 371–287 BC) has survived. Theophrastus’s treatise, together with the pseudo-Aristotelian De mineralibus (On minerals) and the passages on stones in works by Galen, Discorides, Pseudo-Balinus, Al-Kīndī, and al-Fārābī constitute the main sources of the material discussed in this manuscript. Little is known about its author, Al-Tīfāšī (circa 1184–1253), apart from his Algerian origins and the fact that he compiled an anthology of Arabic verses and jokes of sexual and erotic content. Al-Tīfāšī deals with 25 stones, devoting a chapter to each. Each chapter opens with an etymological discussion of the name of the stone, which is followed by a description of the factors causing its formation, the location of the principal mines in which it is found, and an analysis of its main physical properties, including its hardness. He then provides a list of medical and magical uses of the stone and discusses its value and price on the market, taking into account different degrees of purity and the optical properties of the stones available for sale in his time.