The leadville mining district is described in
"Colorado Gold", an article by Ed Raines, and in
'Rocks and Minerals' magazine, Volume 72
September, 1997.
"Leadville District: 3,250,000 ounces (of
gold). Gold occurs in quartz-pyrite veins, in
disseminated mineralization in the porphyritic
rocks of the stocks, and in replacement mantos
along with zinc, lead, and silver ores. More
than one hundred quartz-pyrite-gold veins are
known in the Breece Hill area. Most gold
occurs as microscopic particles, but in the
gold-rich areas of the stocks, gold flakes,
leaves, wires, and spongy masses have been found
(Emmons, Irving, and Loughlin 1927; Behre 1953;
Thompson and Arehart 1990).
Ibex mine (including the Little Jonny, Uncle
Sam, Little Stella, and other mines). Ibex is,
by far, the district's best-known source of fine
gold specimens. Immons, Irving, and Loughlin
(1927) mention that gold specimens were
especially abundant in small seams within the
oxidized ores of the third level, where sixteen
sacks of ore were bagged with at least 50
percent gold. A specimen that is probably from
this location consists of a honeycombed quartz
seam partially covered with crusts of limonite
after pyrite. Very fine flattened wires and
nests of wires are scattered all over one
surface of the seam. The wires are quite small,
measuring .1 to .2 mm across by 1-3 mm in
length.
These researchers also comment on gold found
in the primary sulfide ores of the sixth level.
This deeper location was the source of several
specimens displayed in the Ibex Company's
office. On one specimen, sphalerite crystals
were partially coated by "films" of gold. The
other specimen consisted of both sphalerite and
pyrite crystals on a quartz seam that was shot
through with small vugs containing gold wires
and leaves.
A 5.5-ounce Ibex specimen at the Denver Museum
of Natural History (#11203) consists of
intergrown wires up to 5 cm in length. The
author has observed wires up to 8.5 cm long.
Spongy crystalline masses of wires and flakes up
to 8 cm across have also been observed."
Another article on the Leadville district, "The
mines and minerals of Leadville", written by
John M. Shannon and Geraldine C. Shannon, in the
'Mineralogical Record', Volume 16, May-June,
1985, has some relevance.
"During Campion's days, miners found the
'golden stairs' and 'millionaire's chamber' on
the third level between Numbers 1 and 2 shafts
of the Ibex (Number 1 was the Little Jonny). The
stairs, a steep fault, had wire and sheet gold;
the chamber, a cave, was similarly inlaid. 'It
(the gold) could be pried off with a chisel or
screwdriver,' said one observer" (Gilfillan,
1964). "The gold is pure yellow and 860 fine."
