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 73
re only grown to-gether, but more commonly they penetrate each other inan irregular manner, forming apparently a single crystal.Twins with oblique axes are also common, the plane ofunion being usually one face of the rhombohedron. Thusin calc-spar two rhombohedrons are often joined by a face 63 A…
Precious stones · Building stones · Mineralogy
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