360 A POPULAR TREATISE ON GEMS.
greater
specific gravity; but there is no very certain test by which the real
meerschaum can be distinguished from the composition, and many suppose
that all the heavier descriptions are spurious, though there is no
absolute proof of this being the case. A negative test may, however, be
mentioned: the composition bowls never exhibit those little blemishes
which result from the presence of foreign bodies in the natural
meerschaum; therefore, if a blemish occur in a meerschaum bowl (which
is frequently the case), the genuineness of the bowl is rendered more
probable; but as these do not show until after the bowl has been used
for some time, the test is not of much value.
Very
extensive and valuable collections of meerschaum pipes and mouth-pieces
were exhibited in the London Crystal Palace, from Gotha, of both real
and imitation meerschaum bowls. From Turin, Sardinia, were
elaborately-carved meerschaum pipe-bowls, the sculpturing of which was
very exquisite. From Austria a large collection of massa pipe-bowls and
cigar-tubes, which were manufactured from meerschaum dust; the former
of these articles was elegant, and the execution so good, that they
were with difficulty distinguished from the real meerschaum.
The
importation of meerschaum pipes and cigar-tubes into the United States
has of late become very extensive, and it was estimated at two hundred
thousand dollars the last year.
LAVA.
This
mineral is a compound of several minerals, and is a volcanic
production. It occurs massive, with vesicular or porous marks; has a
splintery and conchoidal fracture; a lustre dull or glistening; is
opaque, and of gray, brown, red, yellow, black, green, and white
colors, of all their shades. It often contains crystals of felspar,
leucite,
