The
californite was exposed in the roadside where a cut nearly 15 feet high
had been blasted through rock. Several masses of the mineral had been
broken up and removed during road construction, and the lead exposed
was further prospected by a tunnel about 16 feet long driven into the
hillside in a N. 70° W. direction.
The
country rock consists of greenish-gray, yellowish-green, and
greenish-black serpentine cut by streaks of gneissic diorite,
hornblende schist, and seams of talc. The serpentine mass in which the
californite occurs is over 200 yards thick and is in contact with
gneissic diorite on the northeast. On the southwest, at a distance of
about 65 yards from the prospect, there is a series of gray and black
slate or phyllite, quartzite, graywacke, and blue and white marble and
limestone. The serpentine has been crushed to lenticular masses with
many slickensided seams. The californite occurs in a belt of badly
fractured serpentine some 12 feet thick with an east-west strike and
dip of about 80° N. Lenses, nodules, and streaks of californite are
irregularly scattered through the gem lead. The streaks range from less
than an inch to several inches thick and the nodules and lenses also
range from the same small size to nearly 3 feet thick. One lenslike
mass exposed in the tunnel was nearly 3 feet across and from it a
streak 3 to 4 inches thick extended several feet to the end of the
tunnel. There is a thin deposit of a hard flesh-colored mineral with a
granular crystalline texture between most of the californite and the
serpentine.
The
color of the californite ranges from bluish green or yellowish green to
white and gray with a tint of pink. Pale yellowish green is the most
common color, and some of this californite grades into darker green and
into white or gray in the same masses. Part of the green, gray, and
white material is translucent and part is opaque. In some of it the
color is evenly distributed through large areas, and some contains a
few darker greenpatches and spots similar to some of the californite
from the C. N. White mine, near Lindsay, in which the patches of color
were shown to be caused by chromium compounds. Seams and cracks or
joints occur through all of the californite, so that flawless specimens
of good color and quality more than 2 or 3 inches thick are rare. Many
of the cracks are not sufficiently pronounced or have been recemented
so that the strength of the stone has not been greatly injured and the
californite can be cut regardless of them if larger pieces are desired.
Larger cracks occur along some of the joint planes and form lines of
easy parting or fracture in the californite.
The
californite locality of the Prethero Bros, and Nat Parker is about 30
miles northeast of Sanger and 32 miles east of Fresno. It is on the
east side of Watts Valley about 1-1/2 miles south of Hawkins
schoolhouse. The prospects are at elevations of about 2,000 feet above
sea level, or some 700 feet above Watts Creek. The mountain side is
steep and has a thin soil cover over talus and debris slopes. The
principal vegetation is brushy live oak, poison oak, and stiff wirelike
grass. The californite has been obtained from several prospect pits in
a northwest-southeast belt. The rock formations are varied, but the
californite occurs in a serpentine complex in which are chloritic and
talcose soapstone phases. Fine and coarse diorite and epidotized
diorite also occur near the californite deposits. Little could be seen
of californite in place at the prospects visited, but it evidently
occurs
