[meteorite-list] NPA, 06-1894 How Kunz recognized diamond in Canyon Diablo

[MARK BOSTICK]

Paper: Delphos Daily Herald
City: Delphos, Ohio
Date: June 21, 1894
Page: 2


DIAMONDS ARE FREAKS

The stones Are Found in the Queerest of Places

     In a report made by George F. Kunz to the U.S. Geological Survey (not 
yet in print) an interesting account is given of an experiment made at 
Chicago during the World's Fair in determining the character of what 
appeared to be a diamond carbon found in a meteorite by Prof. George A. 
Koenig, of the University of Pennsylvania.

     Prof. A. F. Foote, of Philadelphia, obtained a piece of meteorite from 
Canyon Diablo, Arizona, in 1891.  He sent it to Prof. Koenig for 
examination.  The piece weighed about sixteen pounds.  When an attempt was 
made to cut it, it was found to be remarkably hard.  The edge of a half-inch 
chisel was repeatedly broken by it.  One spot in particular, was so hard 
that the tools produced a black powder instead of chips.  When the meteorite 
was being cut, an attempt was made to polish the sections on an emery wheel. 
  The emery wheel was ruined.

     Diamonds had been noted previously in Russian meteoric stones, and 
Prof. Koenig pronounced the black particles from this Arizona to be diamond. 
  The particles of this substance obtained were so minute that the ordinary 
chemical tests could not be applied to them, but Mr.. Krunz suggested at the 
meeting of the Academy of Arts and Sciences that if enough clean grains 
could be obtained to polish a diamond, the nature of the substance would be 
definitely determined.  About 200 pounds of the meteoric iron was examined, 
and specimens which appeared to contain diamonds were dissolved.  The 
exhibition of diamond-cutting in the Mining Building of the World's Fair 
gave the opportunity for trying the experiment, and Tiffany & Co. made 
preparations for the test. A diamond-polishing wheel was specially planed 
downs, and prepared with radiating scratches so as to be easily charge with 
diamond powder.

     The wheel was run at 2,500 revolutions to the minute, and a diamond was 
tried on it for five minutes without any polish resulting.  The wheel was 
then charged with the meteorite powder mixed with oil.  As soon as the 
diamond was placed on the wheel as hissing noise showing that it was being 
cut.  In three minutes one face of the diamond was polished.  After a series 
of experiments with this powder, Mr.. Kunz says he is satisfied that it is 
diamond, "or a substance with the same hardness, color and brilliancy."

     This experiment is interesting only as showing one of the queer freaks 
of nature.  Why a meteorite should be charged with diamond-dust is no 
apparent than is the reason for the discovery of a single diamond in a 
Kentucky field.  There has been but one diamond discovered in Kentucky, 
though certain sections of the State has been studied minutely with a view 
to probable development of diamond mines.  The diamond in the United States 
is almost as great a freak as the diamond-dust in a meteorite.