deservedly,
on account of their singularity; for they were discovered with such
combinations of design as would appear impossible without a hand and
mind to have executed them purposely.
In
fact, the figures formed by metallic oxides inside the agate do not
exist in a natural state exactly as they appear when the stone is cut.
The skilful artist often finds it necessary to cut away some lines,
marks, or spots which would otherwise deprive the design of regularity
; whence it may be said that, in this respect, the lapidary resembles
to a small extent the sculptor who carves the statue from the block,
cutting away the superfluous parts. No little study and cleverness are
requisite in deciding on the best treatment of the spots existing in
the interior of the stone, and in executing the intagli so that they
produce the best effect. Camello Leonardo da Pesaro states that he has
seen a figured agate in which were distinctly represented seven trees
on one even ground. Boëce de Boot declares that he possessed one in
which a mitred bishop was designed ; on another Poujet saw a Turk ;
Caire had one on which was delineated a cock in an attitude of defiance.
Crystallized
agates are those whose mass is divided by numerous fissures into
divisions, which are either square, triangular, or radiating. They are
vitrified, translucent quartz. .
The agate xyloidina, so called from the Greek word ξύλον, wood, is that kind generally designated agatized wood.
The Oriental agate is almost always transparent, and
