230 THE AUSTRIAN YELLOW.
finitely
more beautiful until the royal gem has been transformed by human skill.
But after the touch of the magic wheel there is no substance which can
compare with the diamond for luster, brilliancy and iridescence.
Certain
Indian diamonds finished by the hand of Nature and known as " Naifes,"
are an exception to the rule that rough diamonds are dull looking.
They are seldom or never found now, but were greatly prized by the
natives in olden times and considered superior to the artificially
polished stone. They were octahedral in form, with polished facets. The
primary crystalline form of the diamond is the octahedron, or a figure
of eight sides; but it by no means confines itself to this form alone.
It sometimes assumes twelve-sided shapes, or is merely a cube, or yet
again variations of these figures.
The
atoms composing the diamond tend to place themselves in layers, and the
discovery of this fact facilitated the cutting of the stone, as by
finding the grain a skillful manipulator
