Of this extraordinary tale the concluding sentence alone is the only one worthy of the slightest attention; all the rest is mere legend. Contemporary accounts show that Charles the Bold had no diamond at all similar to the Austrian Yellow either in size or shape; two very important factors in establishing the identity of a diamond.
We have now reached the last great diamond which it is our purpose to chronicle, and it is hoped that the reader has become sufficiently interested in these sparkling pebbles to bear with equanimity a few technical details concerning their nature and the processes which they undergo before becoming ornaments for the crowns of kings or the brooches of queens.
DIAMOND IN THE ROUGH.
That the diamond depends for its beauty almost entirely upon the labor of man is sufficiently known. The rough diamond is seldom a beautiful object, being usually coated with a greenish film which gives it the look of an ordinary pebble. It requires the eye of an adept to recognize any potentiality of sparkle in so dull a lump. The ordinary rock-crystal is infinitely 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 was able to cleave off protuberances at a blow.
The accompanying diagrams represent a certain large diamond both in the rough and after it was cut into a brilliant, and they will help to explain the process of diamond-cutting, which is briefly as follows: The first process is to make lead models of the stone in its actual state and also in the ideal, namely, after it is cut. By this means is found out the most economical way to shape it. The next step is to cleave it toward that shape as far as possible. Cleaving is performed in two ways; by a steel saw strung on a whalebone and coated with diamond dust which saws off the required amount; or by scratching a nick with a diamond point in the direction of the grain and splitting it off with one blow. This latter process, observes an old writer, requires great strength of mind as well as dexterity of hand, for by an unlucky blow a valuable stone may be utterly ruined. Supposing however that the cleavage has been safely performed, the diamond is next fixed into a handle and is so imbedded in a soft cement as to leave exposed only that portion which is to be ground. By means of another diamond similarly imbedded in a handle it is worked down to the requisite shape. The dust from the two grinding diamonds is carefully saved and is used for polishing them. This process is effected by means of a disk of soft iron about a foot in diameter, coated with the diamond dust mixed with olive oil, and made to revolve very rapidly in a horizontal position. The portion of the diamond to be polished is then pressed against the revolving wheel and a high state of polish is thus attained. The grinding of the facets is entirely governed by eye, and such is the dexterity and accuracy attained by good manipulators that perfect roses are cut so small that fifteen hundred of them go to the carat; and when we remember that one hundred and fifty carats go to an ounce we shall have some faint idea of the minuteness of the work.[J]
