The Opal Trip

So, we’re officially headed out to the desert May 19-20. We’re staying a night in Barstow (exciting, I know…), but rockhounding 2 distinct sites, looking for rare minerals. The first stop, I’ve both researched and confirmed in the Califirina guide. The official geologic map for the state points to a paleolithic sedimentary deposit turned metamorphic when the area was intruded upon by subductive volcanism. Igneous intrusions abound, and the desert wind and air has taken it’s toll on the site, as you can see in the low-profile of the mountains. Area in question is to the north west of Barstow, in the light blue cluster bordering the tertiary volcanic activity.


Transposing the two images reveals the terrain change is the area in question, and the run-off and erosion points on the hills are areas to target. Places in the “bake-zone” where, at one time, molten rock came into contact with sedimentary rock. At site 1, we are looking for opals primarily, with a chance at agates or jasper. There is a good chance of picking up crystal here too, in the garnet family.

At site 2, we have to go a tad down the 40 freeway. But not too far. The site will be rich in geodes, and banded agates of various forms. There is a greater percent chance of finding crystal gemstones here as well. The site is visible as steep hills, eroded by desert wind. Area in question is the mixing point of both tertiary and quadentary volcanic areas, where they entered more pre-exsisting sedimentary rock deposits; to the south of Newberry Springs.


Really mixed bag at site 2, so I’m not sure what to expect. The geologic zone indicates more “bake-zone” mineralogy, but the nature of the original geologic unit makes a difference in what minerals appear at the site. For now, I’m cautiously optimistic about what the site holds, but only hitting the ground will give us the solid indicator.


A closer look at target areas for site one makes it clear that I intend to hit the ridges, looking for PRISTINE samples uncovered by rain. Hopefully, there’s a revelation or two to be had out there. I have a feeling the site isn’t done coughing up treasures just yet…

Site two is DEFINITELY MORE CHALLENGING as far as climbing goes. We may NEED to stick to valleys and less ridges. However, we’re looking for minerals in formations more prone to being round, so they may have a chance to have rolled down the hill a ways during the years.


I’m, again, going to attack this site from the perspective of a novice, and assume our better condensations will be in run-off points, rather than trying for a pristine sample at the top of a hill, JUST uncovered.

As you can see, I’ve given our strategy some thought. I want to maximize our efficiency, as collecting precious stones is a big part of our success. I will, of course, have a post on this, but for now, it’s a future engagement, liable to produce some AMAZING finds. Like nothing we could collect locally.

Finally, I’ll have pictures up soon of the most recent batch, the one that finished polishing today. 2 tumbling barrels full of beautiful quartz and feldspar. Great finds a-plenty, from more ancient volcanism. Anyway, go rockhounding sometime.

You might be surprised what you find:



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  1. Pingback: The Rockhounder Honeymoon | Neurochemically Challenged

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