I live in San Francisco and didn't know there was much around here. A friend of mine joined the SFGMS and is going on a trip with them to a turquoise mine in Nevada. It sounds fun. I'm thinking of joining too just for the local classes.
Joined: Tue Jun 03, 2008 4:40 pm Posts: 2408 Location: South Carolina
ya know the san fran bay area is one on the most complex geological places on earth. My aunt sent me a book all about the geology of that area when she visited last year. Holy cow..it was an extremely indepth and complicated study of the different rocks and types and formations of that area. Not much in the way of gems but a geologist mecca! You should see the color coded map of the different rocktypes and stratas..it's like a picasso painting.
_________________ These gems have life in them: their colors speak, say what words fail of.
Joined: Fri Feb 24, 2006 1:20 am Posts: 2558 Location: Southern California, U.S.A.
San Francisco is cosmopolitan geologically as well as culturally. I strongly recommend John McPhee's wonderful book "Assembling California" to anyone with curiosity about our state's amazing geological past. Like all McPhee's geology-oriented books, it reads like a novel and is a cornucopia of fascinating geological information.
Much of the San Francisco region is made up of terranes from all over the earth that smacked into California's coast over a huge timespan thanks to plate tectonics. It makes for jigsaw-puzzle geology. And those processes are all linked to similar ones covered in two other of his absorbing books: "Basin and Range" (Nevada and Utah) and "Rising from the Plains" (Wyoming). A boil-down of all 3 is contained in his "Annals of the Former World."
Joined: Sun Nov 20, 2005 6:00 pm Posts: 87 Location: northern ca
Clear Lake Gem Mining Company of Woodland, California, considerable exploration and development work on a “gemstone” prospect in the SE1/4 of the SE1/4 of sec. 20, t. 12 N. R. 7 W., in 1929. Two large open cuts ( 100 feet log by 10 feet wide by 5 feet deep, and 200 feet long by 20 feet wide by 5 feet deep) and numerous smaller pits were cut in the Perini Hill andesite in search of gem material. The stones, a very clear, high-temperature variety of quartz, occur as irregular masses sprinkled through the andesite. These were originally thought to be hyalite, a variety of opal. Purple cordierite which originally was thought to be amethyst, is also present
Here’s the latitude / longitude numbers for Google Earth 38.868571° -122.652494
I'll bring the corkscrew, the bruschetta w/goat cheese, roasted red peppers and black truffles. Maybe a pyramid of fluted champagne glasses filled with "Dom" and a generous tray of chocolate covered strawberries and smoked Gouda cheese.
Just don't touch my flask. (Whadda ya think I'm made of money?)
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