Described as being made of Tourmaline stone (Rubellite - Madagascar ruby), engraved and originally set in a ring, it represents the seal of Emir 'Ammar who conquered Rametta under Al-Mu'izz. He became a high dignitary at the court of al-Aziz. He was entrusted with the caliph's son, al-Hakim, who was only 11 years old, upon the death of al-'Aziz. He earned the titles of Wasitah (intermediary) and Amin al-Dawlah (the most trusted of the Empire). Translation of the engraved inscription: In the guiding light of Al-'Aziz the fire, of the blood of Emir Ammar. Al-Ḥasan ibn ʿAmmār al-Kalbī, also known by his pseudonym Ibn Ammar (fl. 10th century), was an Arab military commander of the armed forces of the Fatimid Caliphate. A member of the Kalbite dynasty, he was active in the wars against the Byzantine Empire in Sicily in the 960s, leading the capture of Taormina and Rometta, which completed the Muslim conquest of Sicily. Published in Siciliae Nummi Cuphici, by Vincenzo Carascio, printed 1981, Hohner, p. 188 n.150. European private coll.