Springs
and extending southeasterly from the east side of Cameron Cove along
the slopes of the mountains for a distance of 3 miles. Numerous
prospect holes in the Crystal Park region with the less valuable
crystals left on the dumps show the past activities of mineral
collectors. Fine quartz crystals occur at numerous places outside of
the Crystal Park region and especially to the northwest, toward Pikes
Peak, more amazon stone has been found.
The
rock of this region is principally coarse biotite granite composed
chiefly of light flesh-colored potash feldspars, a white plagio-clase
feldspar, gray quartz, and biotite mica. Pegmatite occurs in dikes,
veins, and irregular masses through the granite. The crystals of amazon
stone occur in the cavities or pockets in the pegmatite. The pockets
vary from less than 1 inch to nearly 2 feet across. Some of these
pockets are miarolitic cavities in the granite, around which the
crystallization is coarse and the same as in pegmatite. In some cases
the miarolitic pockets are connected by seams or veinlets, and can be
readily traced for yards. In other cases the pockets are isolated, and
others may or may not be found near by. The pockets are lined with
crystals of amazon stone, smoky and clear quartz; occasionally topaz
and phenacite are present. The crystals of amazon stone are generally
well developed, and vary in size from a fraction of an inch to 3 or 4
inches square. The color ranges from gray to bright green and is often
richer in one portion of a crystal than in another. The crystals from
the shallow prospects are often more or less stained with iron rust
both on their surfaces and along cleavage cracks. The rust may be
removed with oxalic acid to prepare the crystals for mineral
collections and for sale as gem material. Quartz crystals are found
ranging from a fraction of an inch to several inches across, either
singly or in clusters of parallel grown crystals. Some are colorless,
though the majority are more or less clear smoke colored, sometimes
very strongly so. They furnish fine cabinet specimens for mineral
collections. Whitman Cross a and W. F. Hil-lebrand
describe the occurrence of the specimen minerals of this region. Those
observed were microcline, albite, biotite, quartz (smoky and clear),
fluorite, columbite, gothite, hematite, and limonite, arfvedsonite,
astrophyllite, and zircon. As much as a ton of crystals have been found
in one pocket.
Amazon
stone and crystals of the associated specimen and gem materials,
quartz, topaz, and phenacite, were mined by J. D. Endicott during 1908
in the Crystal Peak region 4 miles north of Florissant, Teller County.
The occurrence of these minerals at this locality is evidently similar
to that of the Pikes Peak region. The country rock in each case is
coarse granite. Mr. Endicott states that the crystals are found in
leads of pegmatite, which can be traced from a few feet in some cases
to over a hundred yards in others. In the deposits opened the pegmatite
is nearly in blanket form. The amazon stone occurs in streaks and
pockets in the interior of the "veins" and attains a thickness of 1
foot in places; in other places it is absent. Troughlike depressions
occur in places in the cavities, and in these the amazon stone is
stained and coated with films of oxide of iron. Evidently the troughs
served as channels for a later deposition of limonite from solutions.
Some of the amazon stone is of good gem quality and has a rich green
and blue-green color. Other stones are pale or badly
Minerals from Pikes Peak : Am. Jour. Sci., 3d ser., vol. 24, 1882, pp. 281-286.
