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Synthetic sapphire
Production of this synthetic gem started a few
years later than ruby, greater difficulties being encountered
in reproducing the color.
Appearance The color of medium-light faceted
stones often looks darker at the edges, due to an optical
effect. It may also be colder and grayer than natural sapphires.
It is cut into all the shapes used for the natural stones,
both faceted and cabochon. The cabochon cut is, in fact, the
one that best suits it.
Synthetic sapphires cut en cabochon are the
most convincing and hardest to distinguish from natural stones.
Distinctive features The color, sometimes with an unusual
shade and color zoning, and the absence of bluegreen pleochroism
may distinguish synthetic sapphire from some, but not all,
natural sapphires, given their variability Here, too, the
main.
Distinctive features are internal
and only visible under a lens or microscope: broad bands representing
curved growth lines emphasized by a different depth of color
are much more clearly visible than those of synthetic rubies
if the stone is examined against the light. Sometimes gas
bubbles and minute foreign bodies either separately or in
swarms" follow the growth curves.
Cost As with synthetic ruby, the cost is very low and mainly
accounted for by the cutting process.
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