ma-Pacific Exposition was in the shape of an
elongated shield, about 1-3/4 inches by 1-1/8 inches in size and rather
flat and thin for its spread. It gave in one position a solid surface of
almost pure ruby red which changed to green on tipping the stone to the
opposite direction; $2,000 was asked for the piece.

"_White opal_" is the name applied to the lighter shades of opal which
do not show the bluish-black effect in any position. "_Harlequin opal_"
has rather large areas of definite colors giving somewhat the effect of
a map of the United States in which the different States are in
different colors.

"_Fire opal_" is an orange-red variety. It has some "play" of colors in
addition to its orange-red body color.

"_Opal Matrix_" has tiny specks and films of precious opal distributed
through a dark volcanic rock and the mass is shaped and polished as a
whole.

JADE. "_Jade_" should next receive attention. It is a much abused term.
Under it one may purchase _jadeite_, _nephrite_, _bowenite_,
_amazonite_, or frequently simply _green glass_. The use of the word
ought to be confined to the first two minerals mentioned, namely,
jadeite and nephrite, for they only possess the extreme toughness
together with considerable hardness that we expect of jade. Bowenite,
while tough, is relatively soft and amazonite is brittle and also easily
cleavable, while glass is both soft and brittle.

PERIDOT AND OLIVINE. The mineral "_olivine_" gives us the "_peridot_"
(this name should be kept for the deeper bottle green stones), and the
olive green gems of this same mineral may correctly be called
"_olivine_" or "_chrysolite_." As was explained under garnet, jewelers
frequently use the term "olivine" to designate demantoid garnet. The
term chrysolite is also sometimes incorrectly used for the
greenish-yellow chrysoberyl.

FELDSPAR GEMS. Among the minerals softer than quartz, which are used as
gems, we have also "_feldspar_," which gives us "_moonstone_,"
"_Labradorite_," and "_Amazonite_."

An opalescent form of chalcedony is frequently gathered on California
beaches and polished for tourists under the name of "_California
Moonstone_." This name is unfortunately chosen as the material is not
the same as that of true moonstone and the effect is not so pronounced
or so beautiful. The polished stones show merely a milky cloudiness
without any of that beautiful sheen of the true moonstone.
"_Labradorite_" is usually correctly named. "_