CALCITE
MINING
The posted coordinates are
near a sign, located directly off of S22 in
Anza Borrego Desert State
Park, that describes the
importance of activities in this area during World War II. The
United States Government assigned specialists to this area soon
after the Pearl Harbor attacks to explore the rich calcite deposits
known to exist there. It would become the only site in the United
States for the extraction of optical grade calcite crystals for use
in bomb and gun sites. Eventually a synthetic alternative was
discovered and would replace the natural calcite found in the
mine.
This area is rich in geology, with unique
erosion, tectonic and conglomerate features. There is a well
defined 4WD track (Calcite Mine OHV Trail) that drops down from
S22, otherwise, it is a two mile hike to the Calcite Mine to view
some of the trench style mining pits
To LOG this
CACHE:
1. The mine was sold to
what corporation and operated until what year?
2. Measure the depth (feet) to
the bottom of the mine entrance.
To log this
cache e-mail me the
answer
HERE
.
Calcite: which
gets its name from "chalix" the Greek word for lime, is a very
common mineral (CaCO3 - calcium carbonate), comprising about 4% by
weight of the Earth's crust and is formed in many different
geological environments. There are many uses for calcite, they
include; cements and mortars, production of lime, glass industry,
ornamental stone, chemical and optical uses and as mineral
specimens.
Double refraction: occurs when a
ray of light enters the crystal and due to calcite's unique optical
properties, the ray is split into fast and slow beams. As these two
beams exit the crystal they are bent into two different angles
because the angle is affected by the speed of the beams. A person
viewing into the crystal will see two images. The extremely high
index of refraction of calcite that causes the easily seen double
refraction is also responsible for the pastel rainbow colors that
are seen in calcites that have small fractures.