Diamonds and precious stones, a popular account of gems .. (1874)
Dieulafait, Louis, b. 1830, Sanford, Fanchon, tr · New York, Scribner, Armstrong, and Company · leaf 171
rary, threeof these faces are developed at the expense of the ISO PRECIOUS STONES. other three, and thus we have the crystal repre-sented by Fig. 69. In other cases the crystals are not terminated bypyramids, but by ridges, as in Fig. 70. In thiscase the form of the crystals is greatly altered,… … Fig. 71.—Dodecahedral Quartz. the prismatic portion is quite removed, and thepyramids are applied base to base, the crystal re-presented by Fig. 71 is obtained. It is a dode-cahedron, all of whose faces are equal, and boundedby isosceles triangles. Crystals of this form occur in the midst of…
Precious stones · Diamonds · Gems
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