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The list given
below is not intended to be comprehensive and only includes
the minerals most frequently found. The task of identifying
these gems is not a difficult one, since only about
a dozen minerals were in common use. The more exotic
stones represent just a fraction of ancient engraved
gems. However, it is not always possible to match the
ancient Greek and Latin terminology with known gemstones.
It is a remarkable fact that Pliny gives some three
hundred names to describe stones known and used in his
time.
Chalcedonies or microcrystalline
quartzes
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Sard
is a translucent brown variety of
chalcedony, shading from light yellowish
brown to opaque dark brown. Dark inclusions
can sometimes be observed. Sard is often
difficult to distinguish from cornelian.
The cornelian and sard are the most widely
used stones in Greek and Roman glyptic art.
The name is derived from Sardis in Lydia,
the place where it was chiefly found.
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Cornelian
is a translucent red form of chalcedony, shading
from dark red to golden yellow. The name derives
from the Latin cornum, the red berry of the cornel-tree.
The alternative name carnelian is generally considered
incorrect, but the false etymology from carnis,
'flesh', has popularised its spelling. The whitish
appearance of some ancient specimens is due to
exposure to great heat.
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is used to describe chalcedony
with straight bands of alternating brown or blue
bands. It was the preferred stone for engraving
cameos. The carver would take advantage of the
colours in the layers to show, for instance, cream-coloured
figures on a dark background, or to depict details
of a drapery or a wreath. The term nicolo is used
to describe a Roman banded intaglio with a blue
or brown top layer and a dark brown bottom layer.
Onyx, which derives from the Greek word for fingernail,
a reference to the
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colour of the pale bands, is
the name usually given to a black and white two-layered
banded chalcedony.
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is an opaque form of chalcedony
and the most popular colours were red, orange
and yellow. There is a green variety sprinkled
with red spots popularly called bloodstone or
heliotrope. Yellow and especially red jaspers
became very fashionable for Roman gems in the
second and third centuries A.D. Mottled jasper
with small patches of white, brown, yellow and
black was also occasionally used in the same period.
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Chalcedony
is a microcrystalline form of quartz and its different
colours are due to the impurities that it has
absorbed. The name is also generic, but is convetionally
applied to colourless, grey and blue varieties.
It derives from the name of the city Chalcedon
(modern Kadiköy in Turkey).
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Plasma
is a green variety of chalcedony and often contains
dark inclusions. The green colour is generally
due to the presence of chrome. It is not a very
accurate term, as it is applied to several different
green stones, including aventurine, prase and
chrysoprase.
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Macrocrystalline quartzes
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Rock crystal
is transparent and colourless. It was more popular
in the Greek period than in the Roman, when it
appears only in the first century B.C.. Ancients
believed that rock crystal was a form of petrified
ice, the result of water being frozen at a very
low temperature, the word 'crystal' being derived
from the Greek word for ice. In Asia Minor, Pliny
mentions that a poor variety occurred around Alabanda
and Orthosia in Caria.
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Amethyst
is transparent and ranges in hue from dark purple
to pale mouve. The colour is usually not distributed
evenly in the stone, some parts being lighter,
others darker. The name derives from the Greek
word meaning 'not drunken', which originated from
the belief that the wearing of the stone gave
immunity against the after-effects of indulgence.
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Lapis
Lazuli
is deep blue and sometimes contains brassy specks
of pyrite. It was highly prized since its only
quarries were in Afghanistan, although Persia
was also a possible source. In Roman times lapis
lazuli was seldom used as a gemstone and most
examples date to the second and third centuries
A.D.
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Hematite
is an iron oxide of dark metallic grey appearance.
According to Theophrastos it was given that name
because it looked like congealed blood, the word
'haematite' being derived from the Greek word
for blood. Another explanation for the name is
the red colour that haematite takes when it is
powdered. It was infrequently used in the Greek
period and most examples date from the Roman imperial
period, when it was often made into magical intaglios.
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Garnet
is a crystallised silicate. It is transparent
and ranges in colour from dark red to orange,
and sometimes purple, variants to which different
names were applied in antiquity. It was not used
until the Hellenistic period, when it became particularly
fashionable. Its hardness was superior to that
of quartz and it was thus more difficult to carve.
In Asia Minor, Pliny mentions that it was extracted
around
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the cities
of Alabanda and Orthosia in Caria; the modern
name almandine is a corrupt form of alabandina.
A fiery red variety called lychnis is said by
Pliny to have been found around Orthosia and throughout
Caria. Garnets were very often carved with a curved
surface and, to lighten the colour, the underside
was holowed out.
In addition, glass was used throughout antiquity
as a substitute for expensive gemstones. Some
glass gems were directly engraved as in the same
way as stone gems, other were cast from terracotta
moulds made from the actual engraved stone gems,
both intaglios and cameos. When the result was
not entirely satisfactory, the glass impression
was retouched to give it a sharper edge. Glass
gems could also consist of several layers of varying
colours, to reproduce sardonyx, nicolo, or banded
agate. The glass could be opaque or translucent,
with air bubbles often being visible on the latter
variety. According to Pliny and other ancient
authors, glass gems were often sold as stones
by fraudulent dealers. One story tells us that
the wife of Gallus, in the mid-first century B.C.,
bought a necklace of expencive beads only to find
out that they were cheap glass. The dishonest
seller was caught and duly hauled off to the arena
where after a fearful wait he was confronted by
a capon, not a lion, to the amazement of spectators;
this was said to be a punishment that fitted the
crime. It is clear, however, that most glass gems
were sold as such, being more affordable and available
in a whole range of fancy colours. Demand for
them increased sharply from the first century
B.C. onwards.
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