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 74
ther, as in fig. 86, by a face of the brachydome fPoo, with their chief axes almost at right angles; or, as in fig. 87, by a face of the brachypyramid fP|, the chief axes and the brachypina- coids (o) of the two single crystals meeting at an angle of about 60°. Finally, in fig. 88, two harmotome… … 68 A POPULAR TREATISE ON GEMS. (with a rhombic striae) is parallel to the macropinacoid (q)of the other. In the nionoclinohedric system the most common maclesare those in which the principal axes and the chief sectionsof the two crystals are parallel to each other, and conse-quently the principal…
Precious stones · Building stones · Mineralogy
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