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PRECIOUS STONES.
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51
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Imperialis
of Lambeccius. The jewel was afterwards sold to Henry VIII., and passed
to Mary, who made a present of it to Philip. It is possible it is still
amongst the Spanish jewels in a re-cut state. Fugger's drawing is
reproduced in King's " Precious Stones," with many interesting facts
about the jewel.
Numerous
jewels of the sixteenth century show the original style of cutting
introduced by de Berquem. Kentwaur, in 1562, mentions two types of
cutting, the "point" and the "table." The former was simply the natural
octahedron, with the faces reduced to a perfectly regular form, and
polished ; but the latter had one apex ground down till the flat
surface produced was equal in width to the two adjacent sloping facets
added together, and the opposite apex was likewise ground down to a
plane, but of smaller extent, and all the surfaces polished (Fig. 4).
In the case of a thin stone, the portion below the setting consisted of
a large plane, while the upper portion was cut as the above table.
The
" rose " (p. 55) was produced in the middle of the seventeenth century,
and by 1665 the famous Mogul was cut into a high-crowned rose of 280
carats by the Venetian jeweller Borghis. The "brilliant"
cut was discovered by another Venetian, Peruzzi, towards the end of the
seventeenth century, from experiments on coloured stones. This was
similar in general form to the older table-cut stone, but was worked in
a more elaborate fashion, having thirty-two facets above and
twenty-four below the " girdle," besides the " table " and " collet,"
or fifty-eight facets in all.
Louis de Berquem's essential discovery was the fact that one Diamond will abrade another when the two are
f. 2
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