bsky4463
fully equipped rock polisher
Member since September 2013
Posts: 1,696
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Post by bsky4463 on Sept 12, 2014 11:43:06 GMT -5
to pick up on a topic from another thread, Sabre52 - what characteristics does good mariposite have? this is a slab off of a chunk I have from Cali - exact location? Cool shiny "gold" flecks in it. Wife and friends all say oohh ahhh when they see it. cheers sideA sideB (source/cause of yellow staining?)
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,487
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Post by Sabre52 on Sept 12, 2014 13:16:45 GMT -5
The Mariposite I like best has the strong green and white contrast/banding. As it is a quartz-dolomite-fuschite mix often with included gold and other metallics, it tends to be mixed hardness and a bit difficult to polish beyond sort of a high satin finish. I collected hunks very much like your darker example by hard rock mining in the spring filled gulch where Hwy 49 makes a big bend on the south side of the Merced River Gorge. The orange staining is iron oxide or iron sulfide which shows up a lot in Mariposite and on the mine dumps actually coats the entire exterior of some pieces. It's an interesting material due to the fact is is found in only a very few places in the world, as the name Mariposite for Mariposa County, CA implies. Interesting historical note is the material was first described from John C. Fremont's Pinetree and Josephine Minne where I collected my examples...Mel
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Deleted
Deleted Member
Member since January 1970
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Post by Deleted on Sept 12, 2014 13:19:14 GMT -5
That's a very interesting piece. I'm not sure whether there is a set of good characteristics, so long as it finishes up attractive. What I'm used to seeing is pools and veins of the chrome-rich emerald-green in contrasting white marble: Would be great if there was some actual gold in those flecks, but probably just mica. Should make interesting gems.
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bsky4463
fully equipped rock polisher
Member since September 2013
Posts: 1,696
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Post by bsky4463 on Sept 12, 2014 13:30:43 GMT -5
The Mariposite I like best has the strong green and white contrast/banding. As it is a quartz-dolomite-fuschite mix often with included gold and other metallics, it tends to be mixed hardness and a bit difficult to polish beyond sort of a high satin finish. I collected hunks very much like your darker example by hard rock mining in the spring filled gulch where Hwy 49 makes a big bend on the south side of the Merced River Gorge. The orange staining is iron oxide or iron sulfide which shows up a lot in Mariposite and on the mine dumps actually coats the entire exterior of some pieces. It's an interesting material due to the fact is is found in only a very few places in the world, as the name Mariposite for Mariposa County, CA implies. Interesting historical note is the material was first described from John C. Fremont's Pinetree and Josephine Minne where I collected my examples...Mel Thanks Mel - wealth of knowledge .... I appreciate the insight. The end cut had a white quartz band. I will see if I can cut any cross sections that. I wonder if its worth the effort to figure out if the sample has actual gold in it - not for the extraction value but more for the description/notoriety of the cabs. Cheers
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,487
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Post by Sabre52 on Sept 12, 2014 15:05:18 GMT -5
Bsky: All the mariposite I've collected actually came from gold mine sites and some was actually low grade gold ore. Don't now if that's the case for all the collecting sites. The sparkles are for the most part, the chrome rich mica. I'll have to slice some of my Pinetree stuff and put it under my microscope some time to see if I can see actual gold. Rockstodust: Yup, that's the color pattern I like to see in the material. Looks like you got a better shine than I usually manage too.....Mel Here are a couple of pics of one of two blocks of Mariposite rough I got from the PT&J Mine that made the cut for my Texas move. I like the quartz rich, banded stuff with the real dark chromium mica Side view to show the banding: Slab of Coulterville stuff. Overexposed, a bit darker in real life. I can make it look the right color if I tilt my desktop screen back a bit *L*.
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Deleted
Deleted Member
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Post by Deleted on Sept 12, 2014 18:29:23 GMT -5
I have cut a fair amount of mariposite and have never seen one that looked like that on the top two pics. Interesting to read Mel's description.
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deserthound
spending too much on rocks
Member since December 2013
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Post by deserthound on Sept 12, 2014 20:05:01 GMT -5
i have some that looks just like the stuff you posted. it all came from the same mine in cal. and i have some that looks like all the rest..
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