Help identifying boulder

[murrini]

I am new to rockhounding and was out playing around to see what I could find. The edge of this boulder really caught my eye sticking out of the sand so we dug it out and I can't figure out what it is. We are in very northern California in Southern Trinity County. The rock is very smooth, looks water polished, but all the other rocks on top of it are rough and jagged. This is in a creek bed where it would currently get covered by storm level flows, though 95% of it was covered by sand when I initially found it. It is a very dark blue, like a deep navy, almost black. We didn't realise it wasn't black until we had it mostly dug out to the point in the picture. It is quite hard, we couldn't scratch it with a knife. There is some brownish rust colored rock or oxidation (can't clean it off with a wire brush) in it, mostly on top. In the picture the rock is wet after we cleaned the sand off, I tried to let it dry but it was way too cold out. Dry it seemed to have a bit of a shine to it too though. The entire rock is about 3.5' long and probably 14" across in the middle and we dug down almost 2' and think we found the bottom of it. We couldn't find any other rocks like it. Any ideas would be greatly appreciated, I can't seem to ID it with the rock ID guides, so am wondering if is mineral instead.

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[murrini]

Another picture

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[leonardo]

May be jade but not sure....there was a member on this site from Grants Pass, Oregon ,maybe he can tell you what it is.....

[murrini]

Thanks! After further research last night I had sort of narrowed it down to Jasper, nephrite or onyx, though I don't know if there is onyx in this area. It didn't look streaked with other minerals enough to be a typical Jasper, though Jasper is common in this area. There is nephrite near here, but it is supposed to be found about 10-12 miles away in a different river system, I have found no reports of nephrite in this river, but things seem to maybe be pointing that way, and we think we found another smaller rock that seems to have nephrite characteristics, but it is a lt turquoise color. We are thinking of taking it somewhere for identification, if it is nephrite it makes that boulder more promising!

[leonardo]

I have a friend in Sonora Calif. that use to get alot of Nef. out of the Trinitys.... and remember most of the rivers ran north and south on the west coast millions of years ago.

[Craig]

Very Interesting.
Hopefully JollyRockhound will chime in because he's from that area and I bet he will know what it is.
Nice Find.

[murrini]

Thank you both for your responses! For our first real finds it was an exciting day between that and this other amazingly pretty one we found! Neat to realize there are such pretty things where we have been many times, but never bothered to look! The more research I do the more I'm leaning towards nephrite... Looking at the map and how the land would have changed leonardo's comment about the rivers running north/south completely justify the existence of Jade in that area, I'm thinking it is just so rural that of the few people who might have found it there no one has bothered to publish anything about it. The extreme remoteness out here makes doing research on the area very difficult. It is much easier to get to the sites of Jade for the Eel River and there isn't much at all about those locations. Well, you can count me as addicted to it all now! I'll leave you with a pic of the other great find of the day, don't think it is anything particularly special, but darn pretty (except the pic makes it look grey, it was actually all different shades of blue and photoshop is acting up so I can't do a gamma correction to fix it)! And I'll keep a watch for a hopeful post by JollyRockhound! Thanks again!!

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[jollyrockhound]

Looks like nephrite as well from the pics I have seen serpentine which looks close to that as well

[leonardo]

Yes, but you can scratch serpentine with a knife

[murrini]

We are definitely finding a lot of serpentine too I think, there is a large range of hardnesses in what we are finding, but definitely are finding quite a few that don't, or just barley scratch with a good strong knife. I'm having trouble due to massive amounts of different information out there exactly where the hardness ranges of the serpentine should be vs. Nephrite, should it be fairly easy to scratch or fairly difficult? If we are taking a knife or screwdriver edge and applying a good strong amount of pressure to make it scratch a little what approximate moh are we looking at? It is difficult to research the little nuances like that, and we live well over an hour from the closest mineral shop that might be able to help us, though we are going to stop in there next week when we go to town and see what he can tell us. Thank you very very much for all your help!

[leonardo]

Sounds like you live in Paridise...whats the closest town...spent a whole summer in Forks of the Salmon looking for gold....found some jade in Happy Camp on Indian creek.also found idocraze.

[murrini]

We are in the southern part of the County, between Mad River and Zenia, near Ruth Lake. It takes us about 3 hours to get to Willow Creek, more to get up to the Forks, it's pretty up there though! We usually pack up into the Trinity Alps each summer, kind how we got started looking for stuff, playing around panning for gold up there. It is definitely paradise, right on the edge of tons of Forest Service and not too far from the Yolla Bollies, & people are few & far between. Trinity County in itself is rural enough there are no permanent stoplights in the County that is the size of Rhode Island. And the more we get out hunting the more cool specimens we seem to be finding. Quite astonishing from all the research I have done, didn't seem like there should be much around here at all mineral wise in this part of the county, I was surprised to find they have found platinum, diamonds, garnets and more up there in the northern parts, but we don't even get gold down here.

That idocrase is pretty! I hadn't heard of it. Definitely haven't found any of that!