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I've heard (Brett Foster's mantra) when you find cubes of this along with quartz it a good bet that placer gold is near.(edit) And a pic of an stained crystal that came from the same spot.

nvchris

Could this be galena?

post-861-1239150676_thumb.jpg post-861-1239150718_thumb.jpgpost-861-1239157384_thumb.jpg

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Looks like sulfides Chris. I was playing with a tiny seam recently that threw some real fine color. The rock surrounding the quartz seam was loaded with small pyrite crystals similar to your pic.

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One thing I encountered quite frequently when I was in N Nevada are the pseudomorphs - limonite after pyrite. These crystals used to be pyrite but through chemical alteration- turned into limonite over time.. That's what those two photos on the left look like to me. I really can't tell for sure since you didn't photograph the cubes up close.

Here's a link to a photo of what they look like. I have seen the same cubes in and on matrix.

http://www.desertusa.com/mag06/mar/cubes.html

The crystal on the right, which was found in the same vicinity,is probably iron stained quartz.

Steve

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Ya Dave the old guy that showed me the seam called it porphyry also. Looked real similar to these pics. The stuff was decomposed and broke up pretty easily but the vien sort of pinched out. Does porphyry contain gold sometimes?

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Wes,I've read of gold being found in porphyry dikes on the east belt of the motherlode,small continuos pockets where a cutter or bend in the vein occured.Sometimes the vein or stringer will go in/or out of the vein,perhaps a favorable place to make...that seam you dug on should be followed as the size of the vein dosen't indicate whst it contains,it might widen out..up ahead or down deeper...that's up to you.Just a red clay seam without quartz can be very rich on occasion.I've found gold near narrow porphyry dikes of a bluish or green hue.......then again those rocks in the photo could be a crumbly diorite.. :confused0013: .............Dave

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Meant to write the vein will sometimes go in/out of the dike itself.....anyway,the gold is not continueous in an ore shoot..goes in and out..someplaces rich,some lean..sometimes it stays the same.Hard to explain,easier to demonstrate when actually digging it out.Why leave a spot throwing even a little gold,th're not that common or easy to find.Perhaps you can check out that fine gold you've found with a 10x loupe and see if any is rough,and/or with minute quartz attached.....that often shows what one can expect ahead or down.As you've surely noticed if there is any appreciable amount of clay present,the more you rub,the more fine gold appears....In bulletin #108 from the Ca, state division of mines,November 1934,by Clarence Logan on page 147 is a great description of finding a very rich series of pockets of gold in uranium at the Union-Rathgeb mine near San Andreas in Calaveras county,Ca. in 1887.This was a very thin red seam.. :whoopie: ...Dave

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Hard to tell textures and such from th picture but I would guess intermediate igneous rock (andesite) Looks to have some pyroxene or oxyhornblende in it. How hard is the crystal? Will it scratch steel? Could be something from the aluminum oxide family such as corundum. Does not appear to be from sulphide family and is most definitely not galena.

Get yourself a white porcelain tile and a mineral book. Streak test is quick way to rule things out. Most sulphides have easy to identify streak and hardness tests.

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Dave, What's your experience when a vein carries or starts showing a lot of the little quartz crystals like chris pictured. Good or bad sign? I was told it wasn't such a good sign at the particular location I was at and was wondering if it's some kind of indicator.

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Between my reading all the geology books and your posts, I am learning alot. Please keep this going! :wubu:

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Wes,don't recall finding very many crystals out of a vein.Once in awhile there would be some 1/8th inch clusters in vuggy quartz.if you keep getting gold,keep going(following the lead).keep sampling,you learn as you dig and observe.All the changes in a gold bearing vein are right in front of you.Do you find more color where the vein pinches,where it bends,where there's lot's of clay-gouge or none.where the character of the quartz changes,another vein,cutter,stringer hits it,where the country rock(wall rock encloses the vein) changes,is there a fault in the vein..etc,etc.Follow the yellow.......Dave

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How many sides does that crystal on th right have. It may be the picture but it does not look like a hexagonal form to me. Most quart crystals common habit is hexagonal prisms terminated with a six sided pyramid. Can have twins ands other crystal defects throw you off but my gut says not quartz.

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  • 2 weeks later...

Pic for you Dave. Maybe got a half gram sampling this far. Not much for the amount of work I did, but still fun to grab a bucket now and then. You can see a few of the triangular crystalline shapes if you look close in the pic.

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Wes,if you have any reports for the county your working in you may get a vague idea of what to expect in your diggings.Is it El Dorado?You never mention the tools your using,or how far in you are.Can you show pics of your diggings,including the vein and the tools used?.....very nice rough gold.How do you clean your samples up?.....Grabbing a sack full now and then is how it usually starts until your gold increases and those species start appearing.How far to dig,when to quit is up to you.When was the last time you found gold in a quartz vein,not a real common thing,even in the best gold districts of the motherlode.Sometimes in a vein the gold will quit for a distance and start again,in and out,that's how it is.....now if you only knew whats beyond the point of your pick :confused0013: .........that half gram rough makes me itch,I'd dig on that mother with my crippled up bod and hands if I could get to it easily....if,if....like a line from one of my old poems..wish you owned the word IF........don't look back three years from now to a spot you can't get to any more and be forever wondering,that's up to you.If I can provide any info,post your ????? and Ill tell what I know or think I know.............Dave

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  • 2 weeks later...
  • 2 weeks later...

Wes,you betcha........One of my partners and mentors was the late Chris Porovich,his brother Bob is my good friend and at 96 years old still works hard every day.He would know most Serbian families in Amador,Calaveras and some in Tuolomne counties.Chris and Bob both worked in the famous Carson Hill gold mine and the Calaveras Central gravel gold mine(tertiary)......What was the name and town?.........Did that vein pinch out?................dave

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  • 1 year later...

The big crystal sure looks like milky quartz stained with iron oxides. That is very definitely a gold indicator. If there's a lot more where that came from, I'd get the metal detector out & check the area. Gold is commonly found along with quartz, and often with pyrite or other sulfides. Near the surface these alter, the quartz is corroded (crumbly, 'rotten'). But native gold is not affected, so it eventually falls out of its qtz host and gets washed away. Can then be traced back to it's source. Hope I'm not repeating what everybody already knows. See Bohmker's book on pocket gold in SW Oregon. He explains this, and how to use the knowledge to find minable seams.

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