Hi, fieldtrip friends!
We had terrific sunny weather for Saturday lazulite collecting while the Los Angeles area was getting drenched.
We meet on Saturday morning at a camping area next to the quarry, 2.4 miles east of the Hodge Rd exit. We had an offroader race competing with the trip, but it did not interfere too much as the collecting area was far away enough from the dirt roads. We had three low-clearance vehicles, and two drivers chose to carpool with others.
The location is an unusual iron & phosphate outcrop just south of Barstow, relatively close to where most participants live. The main productive area has been known long ago for lustrous black blades of hematite, an iron oxide, and dark blue grains of lazulite, an Mg-Al phosphate. Everybody collected samples of both minerals in the greenish sericitic rocks at the prospect pit and in the milky quartz vein running down the side of the hill and crossing over the ditch to continue towards the Altuda mine. More lazulite was found as dark blue thin layers filling the fractures in the dark rock. There were some historical reports of wernerite crystals from there, but we could not locate any so far. On the micro side, we also found talc, pink and brown-red rutile, and, surprisingly, purple corundum grains in green sericite.
Past the ditch, yellow-olive layers of another rare mineral, mitridatite, a Ca-Fe phosphate, can be found in sericite below another dark rock outcrop, maybe an intrusive dike, according to some discussions we had. It was initially recognized as a new mineral 100 years ago from the Crimean Peninsula. We also found clear and milky micro apatite balls and crystals in a few prospecting holes near the ditch. The same area has some dark yellow rocks with dark red micro rutile crystals and sharp black octahedrons of magnetite up to a few mm in size.
Please see the visual chronicle of the trip below,