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Doublets
and Triplets
Doublets and triplets are composite stones, with either
two or three layers. The number of possible combinations
of materials usable in making such gems is very large,
and a large variety of composites exists in the gem
trade.
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The
normal purpose of a composite stone is to display a
good color or present a hard upper surface. Seldom is
the bottom portion a genuine stone, although doublets
of diamond on sapphire or spinel are known. Commonly
seen are doublets with garnet tops and pavilions of
glass. |
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The
garnet portion is so thin that its color is dominated by the
color of the glass, which may be blue, green, pink, red, or
blue-green. Colorless doublets are also made. Sometimes a
doublet is created with a hollowed-out crown that is filled
with liquid and cemented to a color¬less base.
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DIAMONDS,
GEMSTONES & CRYSTALS
FACTS & FIGURES |
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Frequently
seen are doublets with colorless sapphire or spinet
crowns and strontium titanate bases. These are
effective diamond imita¬tions in which the
softer titanate provides dispersion color but
is pro¬tected from wear by a resistant top.
Soude
emeralds are made by cementing together components
of colorless quartz, using a green cement to give
color to the gem. Such stones are easily detected
if unset and viewed from the side. Soude emeralds
are also made using colorless spinel.
Other kinds of doublets include those with quartz
top and glass base, or with quartz top and colored-glass
base.
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Opal
doublets consist of slices of opal mounted on
a backing of onyx, ceramic, or opal. An opal triplet
has an added quartz top. |
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Ingeni¬ous
jadeite triplets have been made consisting of translucent
jadeite top and bottom, but with the upper portion hollowed
out and a mass of the same material carefully fitted and cemented
in with a rich green-dyed cement. The resulting stone resembles
the finest "Imperial" jade. |
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