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Geologist to assese large amount jade suspects

Posted by Bruce Johnson  
Bruce Johnson March 07, 2019 05:13PM
Over 10 years have accumulated large stock of jade suspects from N. Californa river gravels - Russian River, Eel, Trinity and others. Will pay for a suitable geologist or other qualified person to come to my home and look at several bins of material to ort them out. I have to move in the future and need to determine what happens to this collection. I live in Mill Valley CA.
I am not a geologist but self-taught - spent time in rock shops, reading and purchasing samples of jades and similar minerals on Ebay to compare. But now need a professional to review what I have. As I said I will pay a commercial rate for time and expenses.

If you cannothelp can you suggestany other way to accomplish this goal?


Bruce Johnson
Daniel Bennett March 07, 2019 08:14PM
one problem I see with what your asking is you may get 3 different geologists with 3 different answers. there are a lot of jade like rocks from California. californite, fransican chert, serpenentine just to name a few. since you have a lot that were found in river gravels you may have all of these. I urge you to embrace some tests on your own. starting with specific gravity and hardness test. you must have enjoyed finding the stuff. testing it and building confidence in your own ability is the next step. no doubt there are some highly qualified people in your area to ask for help but youll never really know with the utmost confidence unless you do the testing yourself. a few tests can go along way.
also I heard somewhere that the original meaning of the word jade is pretty green rock. the point being if you have pretty green rocks than you cant just leave them behind regardless of what they are. feel free to show pictures so we can enjoy your journey with you. -Daniel
Paul Brandes March 07, 2019 09:08PM
Welcome to Mindat, Bruce!

Another thought is to post a few photos on here so we can get a look at these. It certainly won't be like actually touching the samples with our bare hands, but at least it will give us some idea of what we're dealing with. Daniel's suggestion of simple hardness and specific gravity tests will also go a long ways into determining for yourself what you have.
Bruce Johnson March 07, 2019 10:35PM
Thanks! for fun I am attaching one photo which show two small piece in situ

A second photo shows a piece around 8" tall that I rough sanded and polished

The third photo is a piece I have cut and polished
open | download - IMG_0497_edited-1.jpg (1.05 MB)
Bruce Johnson March 07, 2019 10:39PM

This attachment - which I thought was in the last message shows two small suspects in situ.
Ian Nicastro March 08, 2019 07:38AM
There is a lot of green chert in N. California which is often mistaken for Jade. That first photo you posted (of the piece on a stand) looks like real Jade to me, it's similar to specimens in museums that I have seen (NHMLA for instance).
Bruce Johnson March 08, 2019 03:42PM

This was a piece in situ which I did not collect.

Bruce Johnson March 08, 2019 05:40PM
Thanks Daniel.
Sounds like sage advice.

I do have a set of hardness picks and have used them - though some hard serpentines are harder than some softer nephrites?

I looked at specific gravity some time back but failed to find a good simple process to do it. Any suggestions?

As I said oneof my main methods - if you could call it that is to look up images on Google - incl Mindat - and Ebay and to purchase some both those that claim to be jadite or nephrite and those that claim to be related stones - Vesuvianite, serpentine, and others of similar nature. I have purchased jades of different types from different places incluing local California stuff - e.g. Jade Cove. I have talked to rock hunters and even to a few who own sme commercial jade mines - one on the Fraser River. I have purchased Canadian, Artic and Russian samples as well as Burmese and other. - So I do have a madness that is appaching a method. It is just not definitive enough.

In my own dumb way I have mentally categorized many of mine into several types but just don't know what their real names are.

Bruce Johnson March 08, 2019 05:41PM
This was one of the first pieces I found. I have ground and polished it.
Bruce Johnson March 08, 2019 06:21PM

The largest boulder I managed to dig out of s stream and bring back. It has been polished.
Bruce Johnson March 08, 2019 06:49PM

This is a large boulder found in the Far North of California but was too large to take.
Donald B Peck March 10, 2019 06:35PM
The second photo looks like a serpentinite, to me. The first one could be the same, but difficult to tell.
Paul Brandes March 11, 2019 04:24AM
To me, they all look like various forms of serpentinite.
Pretty common in that part of the world near the Josephine Ophiolite.
Daniel Bennett March 11, 2019 07:47PM
those are definitely some pretty green rocks.

easy specific gravity test
using a digital scale weigh the rock. now put a cup of water on the scale and zero the scale. suspend the rock from a string into the cup completely submerged but not touching the cup and observe the weight. divide the two weights and that's it. the more complicated way uses an old fashioned scale that cant be zero'd. use a quartz crystal to test your results which should be 2.6. SG.

serpentine 2.4-2.6, chert 2.6, nephrite 2.9-3.1, californite 3.2-3.5. specific gravity.

the hardness of serpentine is 3-5.5. nephrite is 6-6.5. mohs.
Bruce Johnson March 11, 2019 08:03PM
Thanks so much for the tips. Is there an easy way to do specific graviity for a larger stone?
Douglas Schonewald March 11, 2019 09:32PM
Just break a chip off. The caveat here is if it really a 'jade' it will be very difficult to do that. I've had pieces of 'jade' from Washington state the size of your fist and they are very difficult to break with a 4-5# drilling hammer unless they already have a flaw in them.
D Mike Reinke March 11, 2019 09:44PM
Bruce when I was starting out I would find some large stones and do a crude specific gravity test by putting them in a bucket of water and measuring the volume of displacement and then measuring the dry weight of the stone too of course. Then do the math. It is crude but then rocks are mixes of minerals and you don't know the amount of iron in the mineral so you're going to vary quite a bit but it's a good enough ballpark figure for me. Hope this helps.
Bruce Johnson March 13, 2019 05:28PM

Continuing my series of "suspect jade" from river gravels in N. Cal.
This one is what is referred to as a "wind slick" It is a wind-shaped stone - though found amongst gravels. It is extremely heavy and shows a dark green color in strong light.
Bruce Johnson March 13, 2019 05:38PM

This is a piece of stone picked up in the same N. Cal. river gravels and is what I think of as Serpentine. I have set it to show the color better.
Bruce Johnson March 13, 2019 05:58PM

These are slices of stone from the same locales. They have whitish rind and this dark green stone inside. One photo shows the slice poished and the other the slice with bright light shing through it.
Daniel Bennett March 13, 2019 09:43PM
when you say "extremely heavy" i wonder exactly how heavy? serpentine often has a greasy feel in your hand.
andrew Ilikerocks March 14, 2019 03:00PM
Hello Bruce I am from Sonoma County. I am an experienced Big Sur Jade collector/hound. I have recently joined the mineral and gem club up here. after 9 years of collecting big sur jade. I too recently started hunting up here in the same rivers. Yes there is plenty of nephrite/possibly jadeite in these rivers, verbal confirmation from people whom collect. A lot. But quality varies. I have seen many samples that resemble yours. I have some too. But like you I am not 100% sure as it is different than big sur nephrite. I need to seek out these people again. I do believe that some of what you are showing is "jade", I have some of the same rock. The cab pieces and the river slicks, and that huge boulder looks like the stuff they pull out of Covelo area. I also see lots of blue/green chert in your first pictures. semi translucent almost. I think the problem with the river systems here. Is that no one has done any concrete identification with lab equipment, except with known localities. Anything in this region with quartz veins will be chert/jasper/agate material or something not jade. As in your first picture. Anything with those fracture lines will be chert or another type of chalcedony, color not important. Serpentine or neprhrite do not fracture like that. Nephrite is always harder than serpentine although they can be very close and in matrix together, usually banded/layers/swirls. That wind slick is very suspicious, Russian?, I have some too and the dark green slick is only a rind, I believe, covering 'jade" or something inside. As mine have little windows.

andrew Ilikerocks March 14, 2019 03:02PM
Oh and if its not "jade" then I believe we have some very good quality Serpentine,
andrew Ilikerocks March 14, 2019 03:10PM
The very first picture with a napkin ring at the base or is that a flashlight, not on. I did not see that before the rest of them...That looks very much like Nephrite and probably is. Looks like something I find in big sur, it really does. I have one piece like that from the Russian. I am confident its nephrite but will have some one look at it later. It has the right luster and transperancy. Very different than the chert. Also the way it is naturally rounded, nothing shapes like that, nothing except high quality serpentine. but a hardeness test will determine that. And it is not fractured on the exposed edges like chert. which would be the closest look alike in our area. As far as I know there is not Californite/Versuvinate in our water systems here, Sonoma County...In Humboldt and Trinity it does exist. Oh and be careful hunting in our water ways, lots rough landowners out there.

Edited 1 time(s). Last edit at 03/14/2019 03:22PM by andrew Ilikerocks.
Daniel Bennett March 14, 2019 03:12PM
Daniel Bennett Wrote:
> when you say "extremely heavy" i wonder exactly
> how heavy? serpentine often has a greasy feel in
> your hand.
how heavy in relation to its mass? aka specific gravity. you could go around in circles with "looks like this" or just test it and know.
Bruce Johnson March 14, 2019 10:34PM
Andrew that is a geat response. Too much to answer to. It sounds like we have been poking around similar places and items. The "wind slcik" is mine - not Russian and I may have got it further north like Trinity. A few years ago I got a guide and had spent some months aerial mapping locations in the area of Eureka and south and east. including Happy Camp and circled around 4 different rivers and picked up a wide variety there. MOst other stuff is from the Russian River - where I have a number of spots, the Eel River and Sulphur Creek. - All very geologically active areas,

I have looked at Rockhounding information and visited rock shops and purchased specimens from Ebay - so I have gained much comparative information and can sort the stuff - but am still not sure what it is. What I find and call my "suspects" are really fiver or so different types of materials - some like green jade and some that is gray/white and some like turquoise and many shades of blue and green and some nearly black.

I know Vesuvianite, Happy Camp Jade, and some of the other local look-alikes. I have looked for Jensen Blue - which is documented but exhausted, I have talked to a guy who owns a jade mine on the Fraser river - and wanted to go up there to prospect. But I am getting too old to hop around the sites like I used to.

So my interest is to figure out how to sort my collection and dispose of most of it and so some insight in needed before I do that.
Bruce Johnson March 14, 2019 10:42PM

Here are a few more of the type I showed earlier. They were inside a stone with a thick white rind and inside was a dark blue-green glassy material. I cut this material into some thin slices and shined very bright light through it as well as across the surface. I do not know what this stuff is but like it very much. It is all derived from the same areas where I look for jades - N Cal river gravels.
andrew Ilikerocks March 15, 2019 12:49AM
Hi Bruce,
Beautiful material those close ups. I wish I was home, to take and post pictures, it will be some time. But I think we would find agreement in our collections. Whether its jadeite or nephrite whom knows, lab test. I suspect there could be jadeite jade as the other minerals/rocks would suggest it, Omphacites and other pyroxene group members. I would like to say good eyes on your end. Because I know its not easy looking at 1 million rocks. Personally I think the bulk of the jade is still buried and what we find in the river is only a fragment of what's there. 10 years, that's a long time and lots of material to play with. But hey that's how long I have been hunting big sur. Good luck sorting start with scratch test to separate jade from serpentine? use a typical steel blade though, like swiss army...as a high carbon blade can be harder than nephrite and jadeite. Not sure if you knew that already. I made the mistake of throwing rough jade back in the water...ha ha. My gut told me otherwise.
You may have, as I do, some rocks in a serpentine/jade matrix, very pretty rock. And so a scratch test wont do much there.
Good work on the research of areas. I was about to do the same getting ready for spring. Anxious to see what's out there in nor-cal. I do know the eel and Russian rivers/roads fairly well, and will be there soon.
I know those areas in Sonoma county. and do have some material from the vicinity.
Do you know if you have any Chloromelanite? found in/on Humboldt coast...a type of jadeite!

Also at one time there was a rock club up in Mendocino county...they would know some of your rocks I bet.
Bruce Johnson March 15, 2019 05:36AM

Three more examples of the different types of "suspect" stones I have collected on on the N Cal river gravels. In locating areas to search I look first for Ultramafic formations and then look for accessible gravel beds in those areas. Many of these areas happen to be geologically active and sources of hydro thermal power, and are along the West coast subudction zones. In examining suspect pieces I often test them with a strong light as I have observed jade buyers and sellers to do in the jade markets in Myanmar. The edges of the jade transmits light and the ability of the light to penetrate the stone is often seen as a sign of quality.
Bruce Johnson March 15, 2019 05:44AM

Three more "suspects" of different types including one green and white.
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