MERCATI, Michele.- Michelis Mercati Samminiatensis Metallotheca Opus Posthumum, Auctoritate, & Munificentia Clementis Undecimi Pontificis Maximi...- Romæ: Ex Officina Jo: Mariæ Salvioni Romani in Archigymnasio Sapientiæ. MDCCXVII. [1717].- [8], XIII-LXIV, 378, [17, 1 br.] p.: il.; 38 cm.- E. Michele Mercati (1541-1593), Italian doctor, archaeologist, mineralogist and naturalist, born in San Miniato (Tuscany), was an advisor to Popes Gregory XIII and Sixtus V. Mercati was also superintendent of the Botanical Garden and the “armaria” or office of curiosities, from the Vatican, whose mineral collection he helped develop, but which ended up being dispersed after his death. The respective catalogue, left by Mercati in the original manuscript, would only be published in 1717, in the present edition, which has the following structure: 1 - Front cover; 2 - Engraving representing the offering of the work to the Pope; 3 - Title page; 4 - Dedication to Clement XI (4 p.); 5 - Preface “ad humanissimum lectorem” and text by Carlo Majelli to Giovanni Maria Lancisi (p. xiii-xx); 5 - Portrait of the author; 6 - Vita Michelis Mercati (p. xxi-xxvi); 7 - Various preliminary texts (p. xxvii-xlv); 8 - Allegorical frontispiece; 9 - Dedication by the author to Clement VIII (p. xlix-lii); 10 - Text to the reader and various poems (p. liii-lix); 11 - Index capitum (p. lxi-lxiv). The main text follows (p. 1 to 378) and the “Index rerum” (17, 1 br. p.), at the end. In addition to the initial engraving, the portrait of the author and the allegorical frontispiece, the work is illustrated with 139 figures in the text (12 full pages) and 4 separate engravings (one double). Carefully treated volume (probably washed), lacking the double engraving, before p. xlix, which represents the “armory” room; some margins well restored In the words of Curtis P. Schuh (Bibliography of mineralogy), “a landmark treatise in the history of mineralogy and metallurgy describing what was among the first organized mineralogy museums ever established”. Old ownership on the typographic title page: this book is owned by the count of Vale de Reis household and belongs to its trustee. Recent binding, full parchment, with small flaps and gold decoration the manner the time. Brunet III, 1644; Caillet 7390 (for the 1719 edition); Ward & Carozzi (Emerging Geology), 1541.