The daily Alaskan., 1909-12-23
THE BLACK DIAMOND
It Is One of the CurioSitieS of the
 Mineral Kingdom.
A PUZZLE TO SCIENTISTS.

A PUZZLE TO SCIENTISTS. Nature Has In Some Peculiar Way
 Produced This Rare Form of Carbon
 and Then Thrown Away the Secret
 of Che Proeoss-Found Only In Brazil.
 The term "black diamonds" Is some times josingly applied to ordinary coal which we burn In our furnaces, but the real "black diamonds" of com merce are among the most unique min eral products of the world, and they serve a purpose In the industrial world that makes them of great value The black diamonds are pure carbon and yet fin no outward appearance rcsem- ble tue diamonds which we are occus- toned to wear as ornaments. They are slightly harder than the crystal or gem diamonds aud, in fact, about the hardest substance known.
 Black diamonds, or cartoons, are among tue greatest Curiosities of the mineral Kingdom. They are without crystalline form and are found In IT, regular pieces, ranging in size from half a carat up Co three, four and five hundred carats. They are dark gray, black or brownlsh in color and opaque. The real diamond of the jeweIry trade Is also pure carbon, but translucent and crystalline in form. Two objects so alike in composition could not be found so opposite in appearance as these two forms of carbon.
 Another peculiar thing about the black diamonds is that they are found only in one locality in the world. They come from a very small section of Bra zll not more than 225 miles square in area Outside of this limited territory no pure black diamonds have ever been found.
 What peculiar freak of nature cous- ed the deposition of the black di0- monds ln this section of the world and nowhere else Is one of the mysteries which science has failed to explain. None of them has been found in the great Kimberley diamond regions, where the crystal form of diamonds have for so long been mined
 The whole origin of the black dia- moud is, therefore. a scientific enigma, Naturally the question Is raised, "Of what use is a black diamoud| No one would care Co wear one of these diamonds, which resembles a piece of coal more than a real diamond, and so far no one has popularized the black gems as the black pearl has been. Nevertheless the black diamonds serve most important and useful function in the industrial world.
 This pure black carbon is not only harder than the real diamond, but tougher and not so brittle as the gem. Consequently 1t is of great value for many mechanical purposes and paruc- ularly for boring with diamond drills, In diamond drilling the tips of the drills are studded with carbon, or black diamonds, and when the bores are deep the pressure is so great that the gem diamonds would be crushed in the process. But the carbon resists this continued pressure and slowly eats down Into the rocks.
 In diamond drill work the carbon Is set In circular pieces Of soft steel or iron, called bits, and these bits are at. tached to tubing Armed with these black diamond teeth the drills push their way down under severe pressure to a depth of five and six thousand feet, cutting through the hardest kind of rock. Some black diamonds are much harder than others, and there Is no way to determine by the color the difference In the degree of toughness.
 Black diamonds or pure carbon are not by any means cheap, and the own. CTS of the mines in Brazil where they are gathered are making a good thing out of their monopoly. There is no known substance that can take the place of carbon in drills in boring for gold. silver. copper and other mineral deposits. Before the black diamonds of Brazil were discovered 1t was i'm. possible to make borings.
 When the carbon was first introduce ed in our industries 1t was used in diamond saws for cutting stones, mar ble and similar substances. Then the price advanced so that the carbon was found too costly for such use, and bort was substituted for stone cutting. Bort is really an imperfect crystal or gem diamond. but 1t is too brittle for use ln drills. Consequently bort has talk CD the place of black diamonds for stone cutting and the latter have been restricted almost entirely to diamond drilling purposes.
 The average size of black diamonds used in the drills ranges from two to Ave cOrats, but the larger specimens give much better results. They cost more, but they last longer Conse- quently there is a greater demand for the larger pieces of pure carbon, and the price is sometimes run up to pre- mlum figures for unusual specimens.
 The fear that the supply of black diamonds may some day give out and DaraIvze the diamond drilling Industry