Leipzig, Siegfried Lebrecht Crusius, 1794. Thick 8vo (19.6 x 12.2 x 6.0 cm). xiv, [vi], 1,040, [4], [xv] pp.; two folded engravings, one with 74 different colours. Contemporary marbled boards. Spine with gilt lines and morocco label with gilt title. All edges red. = Rare and important work on oryctognosy (descriptive mineralogy) by Johann Friedrich (or Friederich) Wilhelm Widenmann (1764-1798). Widenmann was a professor in Stuttgart and, as pupil of A. G. Werner, a supporter of the (later prevailing) Plutonist theory of the earth. Ward and Carozzi quote: "Ich habe daher die Schriften des Herrn Werners ganz benutzt und mich nur erlaubt von ihm abzugehen, wo mich meine individuelle Ueberzeugung eines andern belehrte". Handwritten dedication by the author dated Stuttgart, 12 Sept. 1794, on the front flyleaf verso, and on the rear flyleaf recto a note in another old hand on crystals (undated). Boards much rubbed, a dampstain on the left side of the first plate, probably because of glue interacting with watercolour ink; otherwise internally spotless. A very good copy. Ward and Carozzi, 2333.