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About
the Object
This new acquisition is a pendant seal of a seated female figure
by Edward Burch. It was once owned by Sir Joshua Reynolds who wore
it attached to his watch and used it to seal his letters.
Seal-stones & Gem Engraving
The 18th century experienced a revival in gem-engraving, partly
due to a greater interest in the arts of Antiquity. Rome was the
major centre for gem-engraving, but in the second half of the 18th
century London became the most important production centre outside
Italy.
This seal-stone is in the form of an intaglio, in which the image
is engraved on a gemstone so that the design is sunk beneath the
surface of the stone. Once engraved, the stone was simply mounted
into a ring or a fob and used for sealing. When the wax seal is
impressed, the resulting image stands proud.
The stone used here is a type of quartz, called chalcedony. In 1812
an Austrian mineralogist, Friedrich Mohs, developed a 10-point scale
of hardness for such minerals: 1 for talc, 10 for diamond. True
hardstones, like quartz, are 6/7 on the scale. Chalcedony came in
a number of varieties, such as ‘common’ (light-coloured)
chalcedony, cornelian and bloodstone (dark green with small red
deposits). For particularly rich patrons, some engravers would execute
their work on incredibly hard stones, reputedly even diamond.
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