Sunday, May 11, 2008

Thomas Range Pt. 3: Garnet Basin

By now you're probably wondering when this narrative will end. Well, it's almost over. After Bell Hill we went to Garnet Basin. John Holfert gives a great description in his book on Topaz Mountain. We turned back onto the main road from Bell Hill and turned north onto the dirt road heading through the Dell. 1.2 miles later we came to an intersection, with another Fluorspar mine to the west, and turned east to head toward the basin. We parked at the end of the road and the entrance to the collecting site was unmistakeable: two hills rising abruptly on either side of a wash which immediately forked after disappearing into the hills.

The rock in this area (and in much of the Thomas Range) is weird stuff. It looks like swiss cheese where the holes took over. My friend Jones thought we were in a Dr. Seuss book. On the way to the basin, large chunks of this moon-rock lay scattered on the ground. It was soft like pumice and full of fissures and vugs lined with quartz--a good sign. We passed a hillside shot through with long gas tunnels which were partially weathered away from the side--some of them looked like cresting waves. I couldn't believe a place like this existed.

We jumped down into the dry wash and started following it into the canyon, where it forked. We followed the left (north) fork and continued further. The hills on either side became near-vertical, and we realized that Google-Earth doesn't always convey the size of a place--what had looked like a small hills from space, now towered above us like some huge termite colonies.

The wash soon ended in a wall, which during flash floods serves as a waterfall. The book says that between this and another waterfall is a good place to collect, so we climbed around the side and started snooping around in the sand. We hadn't brought a screen, and quickly realized this would be more work than we wanted, so we started climbing up the south side of the wash. Every few feet we'd stop and find somewhere to sit, then look around to see where the garnets were. After a few minutes we started to see them--they're randomly scattered on and in the rock. You can pick them off the matrix with a fingernail, or break up the rock to find them inside. We found that the softer, white rock is the best place to look.

The garnets here are a mixture of Almandine and Spessartine, but all the ones we found were altered by hematite, so they appeared black or silver on the outside. We crushed a few and they were rich, dark red in the center. All in all, we found handfuls of small garnets under 3mm across, and about a teaspoon of larger ones, which we took home. I was looking for a good matrix specimen to take home, but never settled on one. I don't know if the garnets here are world-class, but between the crazy scenery and the abundance of specimens I would definitely recommend a visit.

1 comment:

Kevin said...

The best garnet specimens are definitely found by screening in the large wash west of the two small canyons. But keep in mind, you have to screen LOTS of material to find larger specimens. I have had my best luck when going out shortly after heavy rains pass through the area.

I have also found some absolutely gorgeous garnets in the hills just south of Garnet Basin. They are generally very gemmy, quite small, and best appreciated with a 10x hand lens. Good luck and keep on looking!