are
either of accidental occurrence, or are found where other materials are
being mined in occasional veins or pockets. They are often gathered
with little system on the surface, as are the garnet and peridot in
Arizona and New Mexico, or collected in the beds of streams, or from
decomposing rocks, as is the moss agate in Wyoming Territory, or on
beaches, as the agate, chlorastrolite, and thomsonite at Lake Superior.
Nearly all the gems thus found are sent to the large cities for sale,
sold to the visiting tourists, or sent to other tourist resorts, to be
sold as curios frjm that vicinity. Many of these gems are only known
locally or to mineralogists. Some of them never circulate beyond the
gem collectors of the United States, whose one object is to enrich
their cabinets, with something that possesses the qualities of a
precious stone, viz., beauty and durability.
Diamonds
have occasionally been found at a number of localities in the United
States but the crystals are of infrequent occurrence, and never in
sufficient quantities, to warrant any extended mining for them. The
total number found is not more than two hundred. The largest
authenticated diamond crystal was found opposite Richmond, at
Manchester, Chesterfield County, Virginia, by a laborer engaged. in
grading the streets. Its original weight was 23! carats, but it had a
large flaw in one side, and had been injured by the finder putting it
into an iron furnace, in order to prove its genuineness. A facsimile of
this diamond is represented in Fig. 1 on the colored plate. After
cutting, it weighed I if carats. It passed into the hands of Captain
Samuel Dewey, and was by him named the " Oninoor," or Sea of Light.
John Morrissey once loaned six thousand dollars on it, but, owing to
its poor color, and other imperfections, it probably is not worth more
than ten per cent, of that amount to-day. A number of diamonds weighing
one carat each, have been found in North Carolina, at various times,
from 1846 up to the present time. They are usually found in the gold
washings, associated with gold and other rare minerals. This debris is
usually the result of the old gneissoid, and perhaps, the decomposed
peridotite rocks. A diamond weighing 4J carats was found on the Alfred
Bright Farm in Dysartville, McDowell County, North Carolina, in the
summer of 1886, by the twelve-year-old Willie Chrislie, who was sitting
at a spring, and saw "a pretty trick" about two feet from where he was
sitting. He picked it up, took it home, and laid it on a shelf. Only
after two weeks, did he think of taking it to any one for
identification. It was then sent to New York for valuation. It is
quite perfect, but has a faint yellowish-gray tint. These facts were
authenticated by the writer on the spot. A number of small stones have
also been found in or near the elastic sandstone belt in Georgia, most
of them in the gold washings of Hall County. Here, about forty diamonds
have been found, many of which were of fine quality. These diamonds are
usually met with in the refuse of sluice-boxes and "long toms" used in
mining operations. California has furnished them in many localities.
Professor F. Woehler, of Gottingen, Germany, discovered microscopic
diamonds in the platinum sands of the Trinity River, and in all the
northern counties of the State, drained by ' the Trinity River; also in
Coosa Bay, Oregon, and in Smith River, Del Norte County. Instances have
occurred where fragments of broken diamonds have appeared among the debris cleaned
from the stamping-batteries, which reduce gold ore. At Cherokee Flat,
since 1853, from fifty to sixty diamonds have been found : the largest
one weighing 2\ carats, some of them rose-colored, some yellow,
and some white. The highest price that has ever been paid for a
California diamond in the rough is five hundred dollars.
The
probable x>rigin of the South African diamond is explained by Cohen,
Roscoe, and Lewis as derived from an eruptive pock, which was forced
through beds of carbonaceous shale, thoroughly breaking up the carbon,
so that it was disseminated through the volcanic rock, from "the size
of a pin point to large masses. This heating of the shale, had
released, as Roscoe found, a Tolatile hydrocarbon, from which he thinks the diamond was formed. A
