It
was the opinion of the late Dr. Stelzner that the diamond was
crystallized at great depths and came up with the magma or matrix. The
following liberal translation from a lecture delivered by Dr. Stelzner
before the Isis Society in Dresden on April 20, 1893, gives the views
of this celebrated geologist: —
"
Before I give my own opinion, may I be allowed to recall three
well-known geological facts : first, that various minerals which
compose many of the eruptive rocks, for instance the olivine of certain
basalts, contain liquid carbonic acid, and we must come to the
conclusion that the molten magma under some circumstances must have
been impregnated with carbonic acid ; second, that the blue ground of
Kimberley, as already mentioned by Lewis, has a known resemblance to
many meteorites ; and, third, that a modified form of carbon, besides
graphite, similar to the diamond, has been met with recently in
meteorites.
"If
we take these three facts into consideration, and also remember that in
most of the localities in which diamond-bearing alluvial deposits
appear (Ural, India, Borneo, New South Wales, and in the United
States), serpentine (especially perido-tite) is to be found, we come to
the conclusion that the carbon of the diamond itself crystallized when
this molten mass, rich in magnesium silicate, became cool. In support
of this opinion we find that in some instances diamonds and garnets
(pyrope) are found together, showing that they have the same origin."
For
the illumination of the problem of the formation of diamonds the
experiments of Mr. J. B. Hannay of Glasgow, Professor Dewar, and M.
Moissan/and later of Sir William Crookes, are of the greatest interest
to the scientific world.
The
conversion of a diamond into graphite was effected by Professor Dewar,
publicly, in London, as far back as 1880. Sir William Crookes repeated
the same experiment in a lecture at the Royal Institution of Great
Britain, on June 11, 1897, by placing a diamond in the electric arc
where the temperature was 36000 C, when it was converted into graphite.
Among the first attempts to make artificial diamonds may be mentioned that of Mr. J. B. Hannay of Glasgow, who com-
1 See Appendix VIII.
