Imitations and Reconstruction 225
the assertion that in a genuine natural ruby concentric lines are never noted.
This most important, and at the same time certain and simplest,
distinguishing characteristic, is the more to be regarded, inasmuch as
the specific gravity, the colour, the hardness, and the dichroism—in
other words, all the optical and chemical properties—of the artificial
ruby correspond, more or less, with those of the genuine stone and
consequently the scientific assistance, in this case, fails us
entirely. An experienced gem expert will, moreover, recognise the
genuine ruby by its peculiar, characteristic, soft, silky brilliance,
which is lacking in all artificial rubies.
At
the recent convention of German jewellers in Heidelberg, where the
question as to the nature of the so-called artificial or " scientific"
precious stones was exhaustively discussed and a resolution expressing
an attitude of opposition towards excessive advertisement of these
productions was adopted, Court Jeweller Th. Hei-den, in the name of
the " Association of Jewellers, Gold and Silversmiths of Bavaria,"
spoke in favour of hearing an opinion of a prominent authority in
regard to the entire subject. According to the Journal der Gold-schmiedekunst, this has now been rendered, the well-known mineralogist Prof. Dr. Conrad Oebbeke, of the technical high school in Munich, -5
