Boron, Saturday, Nov 10, 2018
The trip will be exploring the borate area near Boron and neighboring volcanics. The date is Saturday, Nov 10th. We will meet at 9:00AM in the Rio Tinto Visitor Center parking lot. We will take look at the giant borax crystal inside and collect a few crystals of ulexite and kernite in the small material piles in the parking lot. We will look at the pit from the viewing point at the Visitor Center, we will not be able to visit the pit itself though. In order to get there turn off Hwy 58 at Borax Rd (not Boron Rd) and head north. In one mile you’ll enter the Rio Tinto property and the signs will lead you to the Visitor Center. The address is 14486 Borax Rd, Boron. Here are the coordinates: 35°01’46.0″N 117°41’12.9″W (35.029442, -117.686926).
Check it out on Google Maps here: https://goo.gl/maps/wyuhMbhSzL22 and you can also see the location here on their web page: https://www.borax.com/borax-operations/borax-visitor-center
Afterwards we will double back to Hwy 58 and continue towards Boron Rd in order to drive around the huge dumps over to the Saddleback Mountain for opal, magnesite, and calcite vein material. The opal is very strong green fluorescent under shortwave UV light. Under longwave UV light the vein material fluoresces in 3 different colors: white for magnesite, yellow to orange for calcite, and less intense green for opal. The matrix rock is Saddleback Basalt, supposedly the same layer as the base rock in the Boron mine pit. In the vesicles you can potentially find clear labradorite, augite, and quartz pseudomorphs after tridymite, covered with white montmorillonite.
Here are the coordinates for the Saddleback Mountain in case you miss us at the Visitor Center: 35°03’34.2″N 117°37’33.9″W (35.059505, -117.626089)
Google Maps: https://goo.gl/maps/uoqBoLrWBdA2
You can get to it by going 3.6 miles north on the County Line Road after turning off Boron Frontage Rd N which runs parallel to Hwy 58. Four wheel drive is advisable, as the County Line Rd gets sandy. The turnoff towards the mountain gets a little bit rougher last few hundred feet close to the foothills.
The last leg of the trip is focused on microscopic minerals at the “pumice” quarry 1.5 miles northwest of the Saddleback Mountain. You’ll be able to potentially find small but interesting zeolites like heulandite, chabazite and likely phillipsite. In some vesicles you can find very interesting aggregates of clear lustrous hexagonal blades of magnesite. The historical articles also mention micro pseudobrookite and more rare minerals like searlesite and smythite. Hopefully someone can find those too. The quarry is marked as the hard hat area, so please bring your hardhats.
Hope to see you all there!