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 72
Fig. 78. Fig. 79., Fig. 80. rock crystal, in consequence of the tetartohedric characterof its crystallization, often exhibit twins. In these thepyramid P separates into two rhombohedrons J* and z,which, though geometrically similar, are jet physicallydistinct. In fig. 80 the two individuals are…
Precious stones · Building stones · Mineralogy
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