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 48
eas in the tetragonal system n might have any rationalvalue from 1 to oo, in the hexagonal system it can onlyvary from 1 to 2, in consequence of the geometric charac-ter of the figure. When ^=2 the dihexagonal changesinto an hexagonal pyramid of the second kind, whose signis mP2. When m is = oo…
Precious stones · Building stones · Mineralogy
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
![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-236-430.webp)
