substance.
The several reproductions of the various forms and sizes of diamonds
will give the reader some idea of the eccentricities of these stones.
The experiments of Herr W. Luzi1
of Leipsic in the production of artificial figures of corrosion on
rough diamonds are of exceeding interest in the light which they throw
on the crystallization and the probable matrix and genesis of the
diamond.
Until
lately the only appearance of chemical corrosion upon the surface of
rough diamonds was the regular, triangular, negative pyramids, which
were produced through heating the diamonds in the open air, or under
oxygen flame. Herr Luzi has succeeded in producing different and
peculiar kinds of figures. He discovered that the breccia from the
South African diamond mines (that is, the matrix or blue ground), when
in a molten condition, possesses the property of absorbing the diamond
or of changing its shape.
He
describes his experiment as follows : A small quantity of blue ground
was melted in a crucible placed in a Fourquinon-Leclerq furnace at a
temperature of 17700 R., which was the highest temperature
attainable. A diamond with perfectly smooth natural faces was
submerged in this molten mass. A further quantity of blue ground was
then added to the contents of the crucible until it was completely
filled. A tightly fitting cover was placed on the crucible, which was
placed in the furnace and again exposed for thirty minutes to the
greatest heat attainable. When the crucible was cooled the diamond was
removed and found to be
1 "Artificial Figures of Corrosion on Rough Diamonds," Berichte der Deut-schen Che mis chert Gesellschaft, 1892,
