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 35
Fig. 8. Fig. 9. is bounded by four equilateral triangles, has six equal edgeswith faces meeting at 70° 32, and four trigonal angles.The principal axes join the middle points of each two op-posite edges.—Ex., gray-copper ore, boracite, and telvine.(2.) The trigonal dodecahedrons (fig.* 9) are…
Precious stones · Building stones · Mineralogy
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![An illustration from Divina proportione : opera a tutti glingegni perspicaci e curiosi necessaria oue ciascun studioso di philosophia: prospettiua pictura sculptura: architectura: musica: e altre mathematice: suavissima: sotile: e admirabile doctrina consequira: e delecterassi: co[n] varie questione de secretissima scientia (1509)](https://img.insideoutlibrary.com/img/200/ia-divinaproportion00paci-113-297.webp)
