Some
authors confound the jargoon with the jacinth ; but the jargoon has a
specific weight of 4*78, and the jacinth of 3'68 ; the jargoon is
yellowish white, and the jacinth reddish yellow ; the jargoon cannot be
engraved because it is too fragile, but the jacinth is often finely
cut.
XLV.
GIRASOL.
Under this
name is understood a gem which reflects, in a different manner from the
asteria, a combination of rays diverging from a central point like the
sun.
Very
many substances produce this effect, when cnt in a spherical or
semi-spherical form. The adularla, the hydrophane, the Brazilian
chrysolite, the opal quartz, the milky corundums, the calcedony, and
some agates can, by the lapidary, be converted into girasole ; that is,
-when the work is executed in such a manner as to cause the incidental
rays tq converge to the central point.
Nevertheless,
authors say that the girasol can be divided into Oriental and Western,
like gems which are scientifically distinguished. The Oriental girasol
is a vitreous corundum resembling a pale milky sapphire, somewhat
reddish and yellowish, and as a corundum, its specific gravity is
declared to be 4. It reflects a luminous pencil of six rays, at
whatever inclination it is seen. This particular stone is Indian ; and
I have no
