washington state gold ore

anyone happen to know what the host rock is with gold ore in the monte cristo district? ( gold bar/ index washington area)
thanks

hah! i am replying to mine own question. the host rock is serpentinite/ quartz feldspar. and what a glorious day it was when i found it!
hint: look for granite outcrops!

If you can pulverize the serpentine on site in that area then do so. I have found gold in the serpentine from this general area.

If there is Serpentine in that area, then there is probably also Dunite and Peridotite. These two rock types are associated with Platinum. Look for them. Heavy gray grains in the black sand from from creeks in areas with Serpentine, Dunite, and Peridotite, are often an alloy of Osmium and Iridium. I have found that Platinum and Palladium often alloy together in black sands as well. Happy prospecting! Sincerely;Rick :!: P.S. Eclogite, and Pyroxenite are two other rock types found in association with Serpentine. Serpentine and Serpentinite are variations of the same rock type. :!: These rock types are formed by compressive uplift and folding of ancient sea floor. I hope that this information has been of value to you, and everyone else who reads it.

Richard36 said:

If there is Serpentine in that area, then there is probably also Dunite and Peridotite. These two rock types are associated with Platinum. Look for them. Heavy gray grains in the black sand from from creeks in areas with Serpentine, Dunite, and Peridotite, are often an alloy of Osmium and Iridium. I have found that Platinum and Palladium often alloy together in black sands as well. Happy prospecting! Sincerely;Rick :!: P.S. Eclogite, and Pyroxenite are two other rock types found in association with Serpentine. Serpentine and Serpentinite are variations of the same rock type. :!: These rock types are formed by compressive uplift and folding of ancient sea floor. I hope that this information has been of value to you, and everyone else who reads it.

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That information is very helpfull. That you Richard.
Jim

You are welcome. Any questions?

The rock man commeth! ( laugh! ) I am surprised that no one has took me up on my offer to extend my hand in comradery to all those on this forum. Rocks and minerals were my thing long before I became a prospector and assayer. Ask me some questions people.

You may recall that I told you that I know nothing about minerals.

Tell you what I'll do. I have some nice specimens of the gold ore I processed. I'll try to find time to take some pictures for your perusal. Free gold is visible, along with other mineralization. I'd be interested in hearing your comments about the nature of the ore.

I will not be able to post before Monday night at the earliest. Be patient. It could be even later!

Harold

Excellent! I truly do look forward to seeing those photos. Good ore turns me on. Yeah, I hope that I can identify it. If I can't, post it in the Appropriate section of www.fabreminerals.com The moderators there will tell you what it is. Don't shortcut on me now, I still want to see it myself without going to the mineral forum to track it down. ( laugh! ) That was meant to be funny. Anyway, I look forward to it. Sincerely; Rick.

Ok, here's a picture of some samples of the gold ore I processed those many years ago.

The gentleman that provided the ore was a rock hound. He came across the material in the process of pursuing his hobby. His daughter was acquainted with an elderly gentleman (Aldo Gabardi) that was a friend, the same individual that grew the beautiful silver crystals I have shown previously. Through him, we became acquainted.

He was generous to a fault, providing me with several samples, as shown, below. Three of them were saw cut, about ¼" thick, but the upper left hand piece is as it was purchased, tapered from about ¼" to 1" in thickness. Free gold is visible in all specimens, particularly the smallest piece.

The dark areas of the sawn specimens are laden with tiny gold particles that shine because of the saw cut. Other areas color the quartz a tan color from the heavy concentration of gold particles.

The top right piece appears to have a couple bands of what surely must be pyrite, although the bands may also contain gold. The color in those areas is much duller, in keeping with that of pyrite.

Enjoy!

Harold

Beautiful specimens Harold, Thanks.

Wow Harold! those are some excellent samples! Thank you! Alright, the white material is most likely one of the Feldspars, Orthoclase is my guess. It may also be a Carbonate Rock composed of Dolomite. The gray material looks like Galena, a lead sulfide, quite possibly Gold and silver rich, and in your case, it was. Being that these two minerals are found together in this ore suggests that it is of Mesothermal Vein Origin, (390-575 F, and at moderate pressures) and formed in association with Granite. As far as vein systems go, this could just as easily came from a Hydrothermal Environment. This type of mineral environment forms in areas that have undergone volcanism, and, or intrusion by magma, which in turn vaporizes ground water and mixes it with gaseous emanations from the melt, creating either acidic or alkaline fluids that dissolve minerals as the solutions flow upward to the surface, redepositing minerals as the fluid flows, in accordance with the minerals solubility, and solidifying temperature. That is why fractures in rock commonly have seams of material infilling them. this type of vein system is called a Stockwork Vein System, though the system that your ore came from was most likely that of a Massive Metamorphic, or Massive Replacement Deposit. I have similar samples from prospects dug up around here back in the 1860's.

Any and all minerals containing lead, zinc, or copper should be assayed for their precious metal content. These metals are natural collectors of PM's within Hydrothermal Solutions.

Richard36 said:

You are welcome. Any questions?

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Well,
could You give a name of a creek with Dunite in it's bank gravel, please? :roll:
Best Regards,
Hugo

I am not sure of any specific creek names where Dunite can be found as a part of the stream sediment gravels, but Curry county OR. does have PT group metals in the black sands found there. Native PT nuggets are not uncommon as well, from what I have read about my region. So, the best that I can say is for you to go check it out. Hopefully you find a Highgrade pocket, and come out smiling. I hope to hear your story if you do. I Will look through my books as well, and if I can find a creek name with that rock type, I will make an additional post with that information for you. Sincerely; Rick.

Thank You very much, Richard.
Hope, one Day, we will hunt for Pt nuggets and ore together in your beautifull land.
Best Regards,
Hugo

Dunite is a variety of Peridotite, and contains less than 45% total silica, and no quartz. It is composed almost entirely of Olivine, Which gives the rock its recognizable greenish or brownish coloring. In the Cascade Mountains, this rock was formed by differentiation of Basaltic magma while it was in the molten state. These rock types are frequently associated with deposits of Nickel-bearing Pyrrhotite, Chromite (Chromium), Platinum, and rare metals. Prominent mineral occurrences in Peridotite have been found in the Northern Cascades of Washington. Serpentinite Is formed by the metamorphism of Olivine rich intrusions in a water rich environment. These intrusions are usually composed of Peridotite, Pyroxenite, and Lherzolite, sometimes also of Amphibolite (originally metamorphosed from Dolomite rock), and Gabbro. Serpentinite is also the Host Rock for Platinum, Nickel, and Chromium. I hope that this information has been helpful to you and everyone else who reads it. If you or anyone else have any questions pertaining to Economic Geology / Minerology, make a post, or send me a PM. I will respond. Sincerely; Rick...

Speaking of platinum bearing rocks, check this out.

http://www.e-goldprospecting.com/html/gold_lateritic_-_saprolitic_de.html


Mark

Thanks for the link! It does have allot of useful info. I was familiar with the Al, Cu, Au, Ag, & Fe, associations with Bauxite, and Greenstone, but had totally spaced the association of Pt, & Ni with Laterite in association with Bauxite and Greenstone. Good link! The OR. and WA. Cascades are filled with emplacements fitting this description. In my region, the North Santiam, Quartzville, and Blue River mining districts contain contacts fitting this description. An out of publication book that would be of interest on this subject would be "Metaliferous mines of Oregon". It contains the history, production, and geology of all mines in my state from 1840 to 1920, and a few up to 1950. Interesting reading if you can find a copy. I found the copy that I refer to in a public library.

Thanks Rick,
I'm a little more interested in the geology here in N. Ga.
I am a member of a prospecting club http://www.weekendgoldminers.com here that has properties in the Ga. counties mentioned on the link.
The old timers (1930's)probably wouldn't have been looking for pgm's.

You are the "Rock Man" here.

What do you know about the saprolite and auriferous quartz and schists her in N. Ga?
I've found sulfides to be an enemy although possibly profitable..
I am a rockhound just like you. :lol:

Mark