simply
a chemical product made by fusing powdered alumina, colored to imitate
the gem by the addition of a metallic oxide. This scientific ruby,
because it is better and cheaper, has largely taken the place of the reconstructed ruby,
made by melting small fragments of real rubies. These chemical products
when dyed blue pass in a similar way for sapphires.
All
these imitations of the true corundum gems can be detected by an
expert, most of them at first sight and without hesitation. And even in
the much rarer cases when the imitation approaches the real stone very
closely, the former can always be detected under a microscope. In the
real, fine parallel lines of structural strain are seen and the little
enclosures, or bubbles, are irregular in shape, whereas in the
imitation the lines of strain are curved and the "bubbles round.
While
scientific rubies and sapphires have a distinct use as ornaments, they
can never affect the sale of the real gems any more than is the case
with imitation pearls. Aside from the fact that the imitation can
always be ultimately detected, the person desiring to purchase a
ruby, as a ruby, and as a work of beauty and distinction wants a gem which he knows is one of nature's rarities and is therefore possessed
