CFMS Field Trip
to North Edwards/ Castle Butte area in May

by Adam Dean and Shep Koss
CFMS Field Trip South Co-Chairs - 2008, 2009

Field Trips south Report

Adam DeanShep Koss

This was our first overnighter since Wileys Well last Thanksgiving and, thankfully, the weather was much drier. 20 vehicles showed up with 42 sign-ins including kids. The day started brisk, sunny and breezy as is typical for the high desert this time of year. At the meet spot, we were met by Bill DeVelbiss of the Tehachapi and Mojave (Boron) clubs. He's an engineer at the U.S. Borax Mine. His presence was welcome in that, among other things, he brought a presentation book on warnings of poisonous desert creatures including snakes and spiders. He also gave a lecture on the geology of the area and notified us about roads closed due to an Air Force T-38 that crashed two days previously.

We proceeded to the Sierra Pelona Rock Club travertine onyx claim, where we scattered to various pits to pull out some of the desert's most colorful onyx (a calcium carbonate base) with hard rock mining and surface collecting. We collected hundreds of pounds worth in combinations of black, white, gold, red, honey and green. Some had blue agate veining and vugs. The tons of watermelon-sized boulders brought up earlier this year were all gone, which attests to the popularity of this site and material.

As the day grew warmer and windier, Bill returned with live animals of the desert, including tarantulas and "hot" Mojave Green rattlers for show-and-tell. While everyone kept a safe distance, this offered those with cameras a great photo-op.


Later in the day, we drove to a nearby quarry to hammer out chunks of bright milk-and-honey onyx. While climbing that hillside, many collected agate, jasper and chert flat. A few pieces of agatized wood were found. Others drove slightly further to collect brecciated jasper.

As the day ended, most returned home, but a few of us returned to the travertine claim for camping and exploring. A few miles away, we found another travertine outcrop but with different colors. These came in darker shades of tans, dark reds, purples, browns and blacks with much swirling in the patterns. We then returned to camp shortly after nightfall.

The following morning we were greeted by two deafening BOOMS which made our heads ring. The Space Shuttle was coming in for a landing at nearby Edwards AFB, and we watched as it made its wide turn for a landing.

After meeting a half dozen vehicles bringing in 15 new people, we spent another hour at the travertine claim, then drove to the Boron Dry Lakes for its elusive petrified palm wood. It remained elusive, but much more agate, chapinite and opal were collected from the nearby hills and around the dry lakes.

Bill DeVelbiss had returned to tell us that U.S. Borax dumped tons of new tailings in their parking lot for us to collect borate specimens. Driving cross-desert to the mine, it didn't take long for us to fill our bags with large choice borate specimens, some weighing tens of pounds. After a tour of their Visitor's Center, most of us headed for home, but a few remained to continue to explore that mineral-rich part of the Mojave.

After the upcoming tourmaline trip, your CFMS field trip guides (Adam and I) will take our own summer vacations and plan on more trips for the fall. Stay tuned!

From Bill DeVelbiss: I am a member of the Tehachapi and Mojave societies.

My home is near North Edwards, just a few miles south of the Sierra Pelona Travertine claim site, so I was in a great position to participate in the CFMS "Great Onyx Hunt" - May 23-24,2009.

I met with the group of "ROCKERS" at North Edwards to register for the weekend trip. That was the first time I met Shep Koss. I didn't plan to camp overnight since my home was nearby, but I was looking forward to spend both days with the group to explore the area around my home. I have lived here almost six years, so I am familiar with many of the local rock and mineral sites that so many of us enjoy here locally and the many welcome visitors.

After registering, Shep escorted all to the nearby Sierra Pelona travertine site. What a great group this turned out to be. I am not sure how to measure the success value of this event. It certainly had to do with the effort and knowledge of Shep to organize and coordinate the field trip activities, and also how many new friends I met. Just a great weekend.

The first day of the "Great Onyx Hunt" was organized to dig and explore the Sierra Pelona Travertine claim. Several other nearby mineral sites were explored by some of the group.

The second day was just as successful. Shep was the only one to stay overnight at the travertine site. I arrived early and had a one-on-one study session with Shep about the area sites and all the activities he had planned for the day. I left for a couple hours to pick up local friends who would spend the day with me. When I returned, the site was filling with new arrivals and some from the previous day. I was very impressed, but not surprised.

The second day's activities included the Boron Dry Lake bed petrified wood area. This requires "hard digging" several feet below ground. There are several well-established holes that have exposed the below grade material that makes the digging process a little easier.

We also took time to visit the US Borax Mine Visitor Center. All the group members had the opportunity to collect samples of borax, kernite, colemanite and ulexite from ore piles. I work at the mine in the Engineering Department. We are very proud of our Visitor Center and I was glad Shep Koss allowed me to share this activity with the group.

Shep Koss did such a good job to keep this group well informed of the daily activities and coordinated our movements around the area's multiple mineral sites like a pro. He is very knowledgeable about the area, and I learned so much this weekend about area sites I was not familiar with.

I am a new member to mineral clubs. This was one of the first organized field trips I have participated in. With all the new friends, what a good experience!

Thank you CFMS and Sierra Pelona Rock Club and, especially, Shep for an enjoyable, memorable experience. I have learned that all our clubs are dedicated to activities that promote education of mineralogy. The CFMS field trip was very successful: educational, entertaining, and providing fellowship and friendship for member participants that will last years.

From Mo: Thank you so much for leading the Onyx field trip. We would have loved to stay another day except my husband wasn't feeling good.

The trip was very enjoyable. For some reason, finding our own rock was very satisfying. Thank you so much for loaning us equipment and helping get the "milk & honey" onyx. My children loved to find their own "treasure," especially being able to hold their own horned lizard. In fact, they smuggled one up to Orange County until we found out. We had to release it at Camp Pendleton finally.


- Adam & Shep

Pre-Trip Information!

This trip is open to all rockhounds that agree to abide by the AFMS Code of Ethics, the directions of the field trip leader, and practice safe rockhounding. A Consent and Assumption of Risk Waiver of Liability form must be signed upon arriving at the campsite.

WHEN: Saturday May 23 and Sunday May 24, 2009.

WHERE: North Edwards/ Castle Butte area

WHAT: The Great Onyx Hunt

MEET: Saturday May 23, 2009 9 a.m. at the market parking lot on Clay Mine Rd north of the 58 Fwy about 15 miles east of Mojave for orientation and sign in. This market is about one mile north on Clay Mine Road.

From here it's a 15-minute drive to our first stop, the Sierra Pelona Travertine Onyx claim.

SPONSORS: CFMS Field Trip South Co-Chairs

LEADERS: Adam Dean and Shep Koss

WHAT TO BRING: While much surface material is available, be prepared for hard rock mining and digging if desired. Being a high desert locale, the temperatures can be extreme between day and night so dress accordingly.

MATERIAL TO COLLECT: The Sierra Pelona Travertine Onyx Claimclaim has some of the Mojave's most colorful onyx. This onyx offers any combination of black, white, and red, gold, green and honey colors, some with blue agate vugs. Recently the pits were opened by backhoe exposing new large veins and boulders brought up. Also at this site silver lace onyx has been found and vugs containing blue agate. This claim also offers overnight camping and is accessible with most ordinary sedans. Within a few miles of this site other sites offer honey onyx, colorful cabing opal, various agates, jaspers and petrified palm. While most of these sites are sedan accessible, as always, high clearance vehicles are recommended for safer access. Visit for pictures of the site.

ROADS: While the roads are basically traversable in most high clearance sedans, high clearance trucks and SUVs highly recommended.

OVERNIGHTER: This trip will now be an overnighter due to the extensive material in the area. Sunday May 24 will now include agates, jaspers and petrified palm hunts around the Castle Butte/Boron Dry Lakes area. Overnight camping is available at the Sierra Pelona travertine claim which can accommodate RVs and tents. Please bring firewood. Hotel accommodations can be had in Boron (5 miles east) or in Mojave (15 miles west) both on route 58.

Most, but not all, sites can be accessed by passenger car with high clearance. High clearance vehicles are still the recommended vehicle.

The road to the travertine claim site can be traveled with most vehicles with or without trailers if driven with caution.

OTHER SITES: The sites around this claim encompasses many square miles of search areas and borders the Desert Tortoise areas so drive accordingly and bring your camera. Nearby is the US Borax Mine. Open for tours this is open desert with no facilities available so be prepared.

TREAT THE DESERT WITH RESPECT: Please help protect our deserts, tread lightly, and pack-out what you packed-in!

All those attending the collecting trips will be required to fill out a Liability Waiver form.

For further information, please contact:
Adam Dean: (909) 489-4899 or e-mail him:
Shep Koss: (661) 248-0411 (land line) or e-mail:

You should contact us if your interested in participating, The weather can change and without knowing if your going or not we won't be able to give you updates or notify you if the field trip gets cancelled.