THERE’S A LONG, LONG TRAIL A-WINDING - - - - - - - - - - - - - - - - -NEW
MEXICAN MOONSTONE
By Merrill O. Murphy
I have not been down at the Rabb Canyon moonstone site for quite a long
time, and I doubt that more than a few of our members have ever been there.
There are reasons for that. 1) It is quite a few miles down there, 2) one
must walk a few miles off the road on a moderately difficult trail, 3) unless
you have a vehicle with rather high clearance, you will be forced to leave
it where vandals may see it, and 4) you are faced with the choice of camping
overnight or driving another 25 miles or so to find a motel room in Silver
City. Believe me that it is well worth all those troubles.
Back in the 1960’s, another Albuquerqian and I held mining claims on the
moonstone deposit. However, we were not the first to do so. I think that the
first claims may have been worked as far back as the earliest copper mining
in the Silver City area. Then, again, perhaps not. At any rate, those who
tried to mine those wonderful moonstones ran into the same problems that my
partner and I faced. There is no road into the site, so it is very difficult
to bring in equipment. Then, too, great care must be taken when trying to
separate the moonstone from the worthless rock. The old drill-and-blast technique
just shatters the moonstone. The only procedure possible seems to be careful
chiseling using a dull steel chisel and hammer. For the casual collector,
the most practical technique is collecting loose material from the surface
and/or raking the loose sand to uncover loose moonstone pieces.
Ruth Bronson, an old-time facetor from west Albuquerque, became tired, sat
down on a low bank, and scuffed the sand with her feet. In doing so, she uncovered
a chunk of moonstone weighing several pounds. Only parts of the chunk were
cuttable into bright silvery-white stones. Like most of the white moonstone,
this one was nearly opaque but much, much brighter than the moonstone of
India and other eastern countries. This specimen came from the north end of
the site. Pieces taken from the southwest end are generally smaller, but the
moonstone glow is a transparent sky blue and wonderful for faceting small
gems.
Moonstone is a member of the feldspar family of minerals. Feldspars are
the most common of all crystalline minerals. There are numerous feldspars
and feldspar-like minerals. Most of them are listed as orthoclase (potassium-aluminum-silicate
with varying crystal structure) or plagioclase (calcium-sodium-aluminum-silicate
with the calcium and sodium varying with subtypes). The Rabb Canyon moonstone
is a member of the orthoclase group called sanidine. Sanidine is a “high temperature
polymorph of monoclinic orthoclase” and is much less abundant than other
members of the orthoclase family. It tends to form as euhedral crystals with
tetragonal Baveno twinning.
I have two very technical treatises on Rabb Canyon. One is titled, “Shallow,
High-Temperature Pegmatites, Grant County, New Mexico” by V. C. Kelley and
O. T. Branson. It is reasonably readable. The other is titled, “Preservation
of Primary Magmatic Features in Subvolcanic Pegmatites, Aplites, and Granite
From Rabb Park, New Mexico by James D. O’Brient. This second one tends to
use all the tongue-tangling words the author could find in the dictionary.
For example, the O’Brient article uses seven huge words on the first page.
Examples are “consanguineous”, “phaneritic”, and “hypabyssal”. Though tending
toward the complex, both articles contain a great amount of information. Both
should still be available through the University of New Mexico Library and
the New Mexico Institute of Mining and Technology Library.
Now, how does one get to the Rabb Canyon site? Simple. Follow U. S. 25 south
to Truth Or Consequences. About 10 miles south of T Or C, turn west on paved
State Highway #152. Continue west, more or less, through Hillsboro and Kingston.
Stay on State Highway #152, climbing steeply over Emory Pass. Check your odometer
at the top, then drive carefully down the west side of the pass for about
10 miles. At this point, the road flattens momentarily before leaving the
valley and climbs to the top of a low hillside. Slow down and watch carefully
on your right as the road goes gently downward. Watch for an opening in the
trees with a livestock corral at the back of the open space. Drive, perhaps,
50 feet, toward the corral. Then, turn west (to your left) for 75 feet. Stop
and examine the dirt road leading west into a gully. Make sure your vehicle
has enough clearance to continue. IF NOT, YOU MUST PARK IN THE CLEARING OR
DO ENOUGH ROAD WORK TO MAKE CLEARANCE PRACTICAL. Walk or drive down this primitive
road to a shallow valley (Noonday Canyon), where it turns to the north and
crosses a shallow ford. (There may be a trickle of water here). Cross and
continue beside an old fence line until you reach another clearing, a distance
of, perhaps, 200 yards. There is an east-to-west fence and gate just beyond
the clearing. This clearing is the trailhead. If you have driven in, then
pull off the road and park here.
Climb the ridge on the west of the clearing, going, perhaps, 20 to 30 degrees
north of west.You should reach a distinct trail near the top of the ridge.
This trail runs north a short distance to a second gate in the fence mentioned
above. After reaching this second gate, the trail angles and goes nearly west
across the ridge. If, however, you have found no trail and no gate at the
top of the ridge, then go back to the trailhead. Now, follow the dirt road
north no more than 100 yards to the east-west fence. Then, walk west up the
fence line until you reach gate #2 near the top of the ridge. From this ridge-top
gate, the trail leads gently up and down a few hundred yards before diving
abruptly into Rabb Canyon.
Go up Rabb Canyon. There should be pools of water in the canyon bottom.
If you look closely, then you will see bright blue flashes from tiny moonstones
in the water. The canyon turns to the west a short distance upstream, and
the water disappears in the sand. Continue up Rabb Canyon until you see a
shallow arroyo on your right. There may be a trickle of water in the arroyo.
Cross the arroyo and take a trail leading northwest. This trail goes only
a short distance before crossing the arroyo. Follow the trail paralleling
the arroyo, keeping it no more than 50 feet to your left. After about a quarter
mile, the indistinct trail will reach a livestock corral. Turn to the left
and walk to the arroyo bank. About a half truckload of white feldspar should
be visible on the far side. It is opaque, cracked, and shows little adularescence.
It is part of a pegmatite that follows a fissure down from the main deposit.
Get down in the arroyo and go up it no more than 30 yards to a very indistinct
gulch that joins the main arroyo from the west. This gulch leads to the moonstone
site. Follow it more or less to the west. The banks will begin to steepen.
Watch for a trail angling up the right-hand bank. This trail will climb out
to a bowl-like little mesa measuring no more than two or three acres. Majestic
cedar trees stand tall in the bowl, some of the largest cedar trees I have
ever seen. When you climb out of the gulch, continue a short distance west.
You should see the remains of a tiny cabin. Blue moonstone is scattered on
the sands between the cabin remains and the lower edge of a sharp ridge. Silver-white
moonstone comes from the north part of the bowl. Shallow prospects are visible
here and there along the west and north edges of the bowl. You will find
lots of fine but very small bits of blue moonstone. The white moonstone will
be in larger pieces. Few pieces of either will yield good cut stones.
Single moonstone crystals at this site have been reported as large as 13
inches by 13 inches by 20 inches. Quartz crystals as large as three feet long
by 8 inches diameter have also been taken from this site. The quartz varies
from colorless to jet black and smoky. Shallow trenches at the north end
of the deposit have yielded pale amethyst. Some of the large crystals of
quartz show as many as five growth interruptions, indicating numerous periods
of intense volcanic action. There are other minerals, such as biotite, magnetite,
ilmenite, and sphene that have also been reported here. Tiny blue crystals
of sanidine feldspar occur in rhyolite from many places in New Mexico, but
this seems to be the only known pegmatite producing large crystalline sanidine.
Now for a few precautions. First, be careful on the trail down into Rabb
Canyon. It is steep, and there are several places where a stubbed toe can
initiate a painful fall. Second, you will be sharing this wilderness area
with wild animals and semi-domesticated animals, like cattle. The cattle will
probably be no problem, but stay clear of a bull or a cow with a baby calf.
Third, among the wild animals to be aware of are bears, mountain lions, and
rattlesnakes. Bears and lions will generally be more afraid of you than you
are of them. As with cows and their calves, a mama bear or lion is unpredictable
should you come between her and her baby. Always be wary of rattlesnakes.
Several varieties of rattlesnakes reside in the Rabb Canyon area. The most
dangerous variety is a small, dark, gray-green rattler. These blend so well
with their surroundings that they are difficult to see. They are also very
fast. Be attentive to the surroundings, and be careful of where you step and
place your feet.
I once walked alone into the moonstone area to take some pictures. I have
since decided that going alone was a bad idea. I parked my low-built car just
off the paved road in the first clearing. I returned to the clearing several
hours later, unlocked the car door, and placed the camera inside. That is
when I heard a rattling noise. I looked around but saw nothing. Wary, I stood
watching the area where the noise seemed to have originated. The rattle came
again, someone’s discarded tin cans maybe. Then, about 25 feet away, behind
a three-foot boulder, the rattle came again. A patch of dark brown fur showed
momentarily above the boulder. I picked up a fist-size rock from down by
my feet and threw it over the boulder. Thirty pounds of baby bear stuck its
head over the boulder. Another rock launched in his direction sent him waddling
toward shelter. With my car door open, I stood scanning the area, looking
for mama bear. I never did see her, but you can bet she was not far away.
The morale to the story is: when out in the wilds, walk carefully, always
remain on the watch, AND NEVER GO ALONE!