GPS Co-ordinates 34d 45m 00s North 117d 32m 59s West elevation 2852
This is one of the best places in Southern California to be on a
moonless night with a good bright UV light. The landscape will literally
come alive with green and orange florescence the second you turn on your
UV light. The entire landscape will begin to glow. There is little need to
wander around and search because all of the rocks are pretty much the same
mix of Schelite a tungsten ore, Powellite a source of molybdenum and
Scheelite is an important ore of tungsten which is a strategically
important metal. Scheelite is named for the discoverer of tungsten, K. W.
Scheele. Although most of the world wide production of tungsten comes from
the mineral wolframite,
scheelite is especially abundant in the US and provides the United States
with most of its supply.
Scheelite is a popular mineral for collectors. It forms perfect
tetragonal dipyramidal crystals that look very much like octahedrons.
These pseudo-octahedral crystals are sometimes truncated with minor
pyramids, but only on the top and/or bottom points of the crystal; giving
evidence of their true symmetry. Other minerals that form
pseudo-octahedral crystals similar to scheelite include wardite,
Powellite, CaMoO4, is isostructural with
scheelite which is why it forms similar crystals. The two minerals form a
series in which the tungsten of scheelite is substituted for by the
molybdenum of powellite. Powellite fluoresces a yellow color while
scheelite fluoresces a bright blue under short wave ultraviolet light. Of
course since molybdenum can substitute for tungsten, some scheelite
specimens will show a yellow fluorescence.
The crystals of scheelite can look like fluorite
octahedrons which can also fluoresce. However, fluorite has perfect
octahedral cleavage and a lower luster. Massive scheelite has often been
mistaken for massive quartz, but then the fluorescence of scheelite is a
Many prospectors for scheelite have made good use of scheelite's
typically bright blue fluorescence by searching for scheelite deposits by
night with ultraviolet lamps. Many old mines have even been reopened after
examination of the mine shafts with ultraviolet lamps have proven that the
ore is not quite yet exhausted.
From LA take the 14 north to Mojave. Take the 58 for 17.5 miles to the
395 at Kramer Junction. Precede south for another 17 miles to the Princess
Pat mine road turn off (gps 34d45m44s north 117d28m29s west) and make a
right. Go straight west for 4 miles and then follow the trail .9 miles to
the mine. You should try to get there at sundown when you can still see
and wait for it to get dark.
A recent Sierra Pelona Rock Club Field trip
My UV light leaves something to be desired but I think you
will get a feel for the colors of the minerals. In normal light these look
more like desert Caliche or ash.