LAKE SUPERIOR REGION.
A large specimen of amethyst weighing 200 pounds is reported to have been sold by Alexander Meads, of Marquette, Mich.a
The amethyst was found some forty-five years ago in a cave on the north
shore of Lake Superior. It is stated to be a fine specimen.
AZURMALACHITE, MALACHITE, ETC. ARIZONA.
Besides
the true azurmalachite gems, composed only of azurite and malachite,
there are impure forms consisting of smaller amounts of these minerals
mixed through a rock or other mineral matrix. Such is the azurmalachite
from the John Kay mine at Mineral Park, Ariz. This variety appears to
be a badly altered fine-grained white porphyry which has been
brecciated, decomposed, partly silicified, and the seams filled in with
azurite and malachite. Portions of this rock are soft and have a
hardness of 4 to 5, while parts which have been silicified are harder
through the presence of much free quartz. The azurite and malachite
occur in veinlets or seams and irregular masses through the rock. The
veinlets range from paper thickness to an eighth of an inch thick and
are very numerous in some specimens. These seams cut each other at
various angles and ramify throughout the rock in an irregular manner.
In places blue azurite is the principal colored minÂeral, in others
green malachite, while the two often occur in the same specimen. The
azurite veinlets appear to have been introduced later than the
malachite. Brecciation of the rock and cementation by copper carbonates
has been far reaching, so that some of the material has a marked
speckled appearance.
NEVADA.
Mr. William KlejT,
of Denver, Colo., kindly sent to the office of the Survey a gem cut
from a copper ore obtained from a mine in Nevada by I. F. Peck, of
Denver. The stone consists of granular quartz with much blue azurite in
the interstices. It resembles chrysocolla in appearance. As a souvenir
gem it should find a market in the tourist trade.
BERYL, AQUAMARINE, ETC.
COLORADO.
The
Mount Antero locality in Chaffee County, Colo., has furnished many fine
specimens and considerable gem beryl, topaz, phenacite, and quartz
crystals. These gems would doubtless be mined reguÂlarly if the
locality were more accessible. The great elevation of the deposits,
with the accompanying dangers from landslides on the steep talus
slopes, exposure to severe thunderstorms, difficulty of transporting
tools and supplies, and the short season (two to three months) when it
is possible to work, has necessarily limited extensive development of
these deposits. Practically all of the workings are simply pits from 4
to 8 feet in width and depth, and many consist of but one or two blasts
in favorable places. Gem deposits have been found on the top of White
Mountain at an elevation of about 13,900
o Manufacturing Jeweler, August 13, 1908.
