A popular treatise on gems, in reference to their scientific value; a guide for the teacher of natural sciences, the jeweller, and amateur: together with a description of the elements of mineralogy, and all ornamental and architectural materials .. (1859)
Feuchtwanger, Lewis. [from old catalog] · New York, D. Appleton & company · leaf 30
at 90°, and eight trigonal angles. The principal axes jointhe centre points of any two opposite faces.—Examples arefluor spar, galena, boracite. 2. The octahedron (fig. 2), bounded hj eight equilateral•triangles, has twelve equal edges, with planes meeting at 109° 28, and six tetragonal angles. The…
Precious stones · Building stones · Mineralogy
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
![An illustration from One thousand processes in manufactures and experiments in chemistry / [Colin Mackenzie]. (1825)](https://img.insideoutlibrary.com/img/200/wellcome-wellcome_b29307867-270-5.webp)
