choochoorocks
starting to spend too much on rocks
Rock hounding
Member since April 2020
Posts: 178
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Post by choochoorocks on Dec 25, 2020 14:27:48 GMT -5
I found a few pieces of this recently. Some pieces are more translucent than others, and they vary from green to smoky grey. The one in the pictures is green and fairly translucent. Its surfaces are mostly curved, and I see some small conchoidal fractures. Is this a quartz or a chalcedony? If the latter, would this be called a chrysoprase?    |
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Post by RickB on Dec 25, 2020 16:01:08 GMT -5
I'm thinking it could be jade but am not an authority on it. Perhaps someone that is will add some input.
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Post by victor1941 on Dec 25, 2020 17:29:09 GMT -5
Green agate rough from India may also look like this sample.
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Post by rmf on Dec 25, 2020 18:21:37 GMT -5
I would say the fracture is subconcoidal and mildly waxy. I would call that agate not chert but you pay your money and make your choice we are diagnosing from a picture. the color is not as bright as I would expect chrysoprase to be but it could be mtorolite with the color coming from chromium. Normally mtorolite has a pattern which can be seen when sawed where chrysoprase has no pattern. I would typically expect chert to be more opaque.
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Post by stephan on Dec 26, 2020 1:29:28 GMT -5
It’s always helpful to provide as much detail about physical characteristics as possible. Where it was found can be helpful too
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Post by amygdule on Dec 26, 2020 15:53:25 GMT -5
I found a few pieces of this recently. Some pieces are more translucent than others, and they vary from green to smoky grey. The one in the pictures is green and fairly translucent. Its surfaces are mostly curved, and I see some small conchoidal fractures. Is this a quartz or a chalcedony? If the latter, would this be called a chrysoprase? Where is this stuff from, Northern California ? It looks like some of the green chalcedony that I find on the Oregon Coast. No on the chrysoprase. |
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Post by amygdule on Dec 26, 2020 17:29:38 GMT -5
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choochoorocks
starting to spend too much on rocks
Rock hounding
Member since April 2020
Posts: 178
|
Post by choochoorocks on Dec 26, 2020 23:03:35 GMT -5
Thanks all for your replies so far! I tested two pieces for specific gravity and it came out to around 2.6. So that rules out jade. From searching online, I see that the specific gravity of californite is 3 or above, so I guess that also rules out californite. (I didn't know californite was so beautiful until I watched the video; thanks amygdule!) Location-wise, I found it in N. California. Based on the images I found online, I think mtorolite may be the closest match, although the stuff I found mostly wasn't as nice and green as the images online. I cut two pieces with my tile saw yesterday. One piece is dark, heavily fractured, and shows just a hint of green. The other piece is a light vibrant green with yellow and white. At this point, would it be safe to say that this material is green chalcedony? What gives it its green?   |
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Post by amygdule on Dec 27, 2020 0:07:46 GMT -5
Sounds like you need to do a scratch test to check its Mohs hardness. forum.rocktumblinghobby.com/thread/18656/mineral-hardness-scratch-testChalcedony is 7, and Serpentine ranges from 2.5 to 5.5 on the mohs scale. It could be Serpentine depending on the geology of the area it's from. Serpentine - Gemdat.orgThe green chalcedony that I find is of volcanic origin. I figured it was colored with iron. I don't know. I tried to take some pictures, but they didn't turn out any good. Here's a piece that I dug out of the basalt bedrock along the seashore.   |
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choochoorocks
starting to spend too much on rocks
Rock hounding
Member since April 2020
Posts: 178
|
Post by choochoorocks on Dec 27, 2020 3:15:37 GMT -5
Ok, so a steel knife leaves a streak of silver on the material. Definitely hard.
Amygdule, how thick is the sample in your second picture? It looks pretty clear. My vibrant green one also has the yellow present in yours, but I'm unsure how transparent it is. I'll try to get some slices soon and will post here. Assuming we have the same thing, what is the best use for this material? Have you tried tumbling it?
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Post by rockjunquie on Dec 27, 2020 9:00:11 GMT -5
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Post by stephan on Dec 27, 2020 11:46:34 GMT -5
I know a lot of people don’t want to give up the location of “their” secret hunting grounds, but Northern California isn’t really specific enough. We font need GPS coordinates, but a city, county, geographical feature (“neat Mount ___”) is always helpful.
Based on what you’ve told us, I’m agreeing with the chert or chalcedony diagnosis.
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pizzano
Cave Dweller 
Member since February 2018
Posts: 1,390
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Post by pizzano on Dec 27, 2020 13:43:49 GMT -5
Don't bother with the GPS coordinates if you're keeping a secret..........LOL
Just give me a County and quadrant........I'll take it from there and search the foundation/formations tables.....it won't pin-point an exact location........!
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Post by amygdule on Dec 27, 2020 23:53:34 GMT -5
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choochoorocks
starting to spend too much on rocks
Rock hounding
Member since April 2020
Posts: 178
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Post by choochoorocks on Dec 28, 2020 0:52:35 GMT -5
I found this in Santa Clara county, if that helps further. I see signs that others have collected from that spot as well, so not sure about etiquette for disclosing more.
I put some pieces in my tumbler today and will see how that turns out.
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pizzano
Cave Dweller
Member since February 2018
Posts: 1,390
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Post by pizzano on Dec 28, 2020 9:40:54 GMT -5
I found this in Santa Clara county, if that helps further. I see signs that others have collected from that spot as well, so not sure about etiquette for disclosing more. I put some pieces in my tumbler today and will see how that turns out. "etiquette for disclosing more"..........?.......sounds like a personal issue...!
Worry not, few, if any here at RTH, are claim jumpers or lying in wait to gobble up ones "secret" stash.........lol
We share information freely here, some have favorite locations held under-wraps, but for the most part, we share in order to better serve everyone's interest.
Santa Clara County has many interesting locations a few here have frequented, often.....!
Morgan Hill Black Mountain Red Mountain Oak Hill Santa Cruz Mountains Sugerloaf Calaveras Valley Los Gatos Douglas Ranch New Alamaden Ect, Ect, Ect................
The list is extensive, many locations are privately maintained or within Federal/State BLM jurisdictions.........most, if not all, really valuable and important material is and has been privately owned and mined for ages............very little from that County, brought to the RTH table, is a secret.
Here's a good link, that supports the industry, we use often to gather information related to our finds. Don't be overwhelmed by it's complexity, it's pretty user friendly and should help you narrow down your curiosity........:
If you'd like to "dig" further........other, more "scientific" links can be provided........free of charge and published for public consumption.......and Welcome to the RTH world of information sharing.
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choochoorocks
starting to spend too much on rocks
Rock hounding
Member since April 2020
Posts: 178
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Post by choochoorocks on Dec 28, 2020 12:19:04 GMT -5
I found this material in Morgan Hill. Has anyone here collected it?
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pizzano
Cave Dweller
Member since February 2018
Posts: 1,390
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Post by pizzano on Dec 28, 2020 13:31:16 GMT -5
Every location named has had visitors from this website over the years........Morgan Hill having been one of the favorites until circumstances surrounding that area changed when private ownership got involved.........I'm sure there will be a few here that will chime in......eventually.
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