sheltie
freely admits to licking rocks
Member since January 2012
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Post by sheltie on Aug 11, 2012 17:23:18 GMT -5
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rockingthenorth
fully equipped rock polisher
Member since January 2012
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Post by rockingthenorth on Aug 11, 2012 17:31:28 GMT -5
Some of them look like quarts to me
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Post by jakesrocks on Aug 11, 2012 18:43:15 GMT -5
They all look like massive quartz to me. Depending on where you found them, you might want to run a metal detector over them. Might be gold in them thar rocks.
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Post by helens on Aug 11, 2012 19:02:02 GMT -5
Well according to what I've read, all 3 are essentially the same mineral. Agate and Jasper are the same thing too... agate is translucent/transparent, and jasper is opaque. And quartz is the 'simplest' form of agate... or put more accurately, agate is complex quartz:). To complicate matters more, glass is melted quartz (sand), with the addition of some other chemicals that results in softening. Obsidian is a natural form of glass. Here is a better explanation from a university site of quartz/agate: hyperphysics.phy-astr.gsu.edu/hbase/geophys/qagate.html
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
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Post by Sabre52 on Aug 11, 2012 21:07:05 GMT -5
Those are massive quartz. Agate and chalcedony, which is basically clear to whitish agate, are microcrystalline ( cryptocrystalline) quartz and jasper is too except perhaps more fibrous, included and opaque....Mel
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Post by mohs on Aug 11, 2012 21:59:49 GMT -5
is that Sedona? geez yes! you might have gold in thar
anyone have an explanation of why gold and quartz have a tendency to form together?
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Sabre52
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Me and my gal, Rosie
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Post by Sabre52 on Aug 11, 2012 23:00:22 GMT -5
OK, not a geologist but I believe quartz and gold are both liquid hydrothermal solutions that form at the end of magma eruptions. As the host rocks cool, voids and fissures form and the liquid quartz, with liquid gold and other liquid metals flows into and fills the cracks and voids. When the liquid cools this forms quartz veins and pockets containing gold and various other metallic ores....Mel
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Post by helens on Aug 11, 2012 23:22:06 GMT -5
How interesting! Soooooo.... say there's gold in the quartz... um... how do you get it out?? Wouldn't you have to smash up your quartz?
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Post by mohs on Aug 11, 2012 23:44:46 GMT -5
sounds good Mel and being that quartz is such an enduring rock I guess it is only natural for it be found often as gold bearing I mean those quartz veins last forever- so quartz is a good protectorate have you ever visited the Vulture Mine ? if not-- I'd put on your list of must see's this my prized piece of Vulture gold bearing quartz
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herchenx
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Post by herchenx on Aug 11, 2012 23:51:36 GMT -5
Quartz will have a blocky fracture, following the crystal "grain" - agate, chalcedony, chert, flint, jasper all have no grain to speak of and will tend to fracture in circular or semi-circular conchoidal fracture. Agate, chalcedony etc. are also typically much harder.
You can break quartz or find broken pieces of it and see the crystalline grain. Shattered chalcedony and agate will have the scalloped, "flint-knapped" appearance.
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sheltie
freely admits to licking rocks
Member since January 2012
Posts: 982
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Post by sheltie on Aug 12, 2012 9:23:00 GMT -5
Quartz will have a blocky fracture, following the crystal "grain" - agate, chalcedony, chert, flint, jasper all have no grain to speak of and will tend to fracture in circular or semi-circular conchoidal fracture. Agate, chalcedony etc. are also typically much harder. You can break quartz or find broken pieces of it and see the crystalline grain. Shattered chalcedony and agate will have the scalloped, "flint-knapped" appearance. What a great explanation! Even I can understand this. Is the fact that I found all this quartz in an field with granite outcropping just a coincidence or is that one of the places where it is commonly found? Also, that particular area has no known history of gold so I won't get too excited. The fact that there were so many different colors, mosses and dendritic material in the quartz is what confused me about whether it was quartz. Also the fact that I did find a great deal of agates in the area. Thanks for the explanation.
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Sabre52
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Me and my gal, Rosie
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Post by Sabre52 on Aug 12, 2012 12:10:23 GMT -5
Ed, Yep quartz is much more resistant than most host rocks so it's whats left over after the base rock has eroded. Then of course, eventually the quartz breaks down too so the free gold finds it's way into alluvial deposits. Only gold mines I've ever visited were on the ranches neighboring my own up in Mariposa County, Calif. Most were hardrock mines or wire gold in quartz. Wish I had photographed one my buddy and I found a few years ago. Someone had driven a shaft into a sold megalithic mountain of red brecciated jasper ( kind of like red Stone Canyon Jasper). This was not far from the Hornitos Brecciated Jasper site so I'd assume it was a related deposit. Must have been one heck of a hard job driving the shaft into the rock because the jasper was so solid you couldn't even break it with your rock hammer. We didn't go into the shaft because there was mountain lion poop and tracks all around the entrance. Got to say though , when I saw that jasper in the sun, it flat took my breath away. Remarkable beautiful sight!.
Helen, Most massive quartz does not have recoverable amounts of gold but in certain regions, a lot of it does. Up at our Hornitos ranch, the poppy jasper even contained included gold bearing pyrite. I even have a cab made from it and I made a neighbor, who let me rockhunt his ranch, a his and her buckle set from jasper I found on their hill that had gold flecks all through it. Old Lowell ( elementary) may have gotten a bunch of that jasper when he cleaned out some of my yard rock piles prior to my move..Mel
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Post by mohs on Aug 12, 2012 12:20:35 GMT -5
O yeah smashing quartz for the gold is an old family tradition !
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Post by mohs on Aug 12, 2012 12:21:12 GMT -5
mostly
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Deleted
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Post by Deleted on Aug 12, 2012 14:30:17 GMT -5
There is a lot of crushing and chemicals involved and they have made a real mess out of some areas because of it. Jim
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Post by mohs on Aug 12, 2012 15:44:45 GMT -5
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
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Post by Sabre52 on Aug 12, 2012 17:48:39 GMT -5
If you want to see gold in quartz jewlery and are ever in Mariposa , California for the annual gem show do not miss it. Lots of gold in quartz around there and a lot of that kind of jewelry at that show. There was also a jewelry store in Coulterville, CA that had a lot of it. If it's still open, the California State Mineral Museum is in Mariposa too. Very cool place to visit! I lived not far from there part time when we had the ranch and Mariposa and the surrounding gold country are wonderful places to visit ....Mel
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Post by helens on Aug 12, 2012 22:28:35 GMT -5
Holy cow, that matchbox is something Ed!!! I am bugeyed. Have no idea what that map is tho...
Mel, thanks for the info:). I looked it up online, and seems to me that slabbed quartz with gold hunks is more valuable than the gold. If you can do that, no reason to crush up your gold!!!
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