Henry
spending too much on rocks
Member since January 2013
Posts: 452
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Post by Henry on Apr 11, 2015 18:45:26 GMT -5
Hello everyone. Nothing spectacular to post. This is my meager large handful of dinky Bolinas "oil agates". The area has become quite busy as of late.   |
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Post by gingerkid on Apr 11, 2015 19:08:55 GMT -5
I like your Bolina oil agates, Henry, but gotta ask a stupid question. Why are they called oil agates? The look like they've already been tumbled and "slick" as if they were in oil. I really like the clear and peach-colored ones. Did you find any whale bone?? |
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Post by gingerkid on Apr 11, 2015 19:21:07 GMT -5
Started wondering again about your bolinas. Do they have water or some other substance in them like enhydro quartz?
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jamesp
Cave Dweller 
Member since October 2012
Posts: 36,612
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Post by jamesp on Apr 11, 2015 19:33:14 GMT -5
I like those bolina babies.
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Henry
spending too much on rocks
Member since January 2013
Posts: 452
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Post by Henry on Apr 11, 2015 19:34:31 GMT -5
Hey there gingerkid. Basically they are wet from cleaning them off. As far as the geology behind them...I haven't a clue other than they are called "oil agates" because of their color. And as far as the whale bone goes....nope. I do have two pieces that are posted in "identification". They're nothing special, but I am curious what caused the striations and patterns in both of them.
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Post by gingerkid on Apr 11, 2015 19:39:36 GMT -5
Thanks, Henry! I found a webpage for you. (I cheated and looked up bolina agates) I hoped you would find some whale bone today on your trip. This webpage has some info about the bolinas and whale bone. rockhoundtimes.blogspot.com/2013/05/field-trip-agate-beach-bolinas.htmlFrom what the website mentions, the black inclusions or specks in the bolina agates are believed to be suspended oil. I saw your other two pretty finds that you posted. |
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Henry
spending too much on rocks
Member since January 2013
Posts: 452
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Post by Henry on Apr 11, 2015 19:46:44 GMT -5
Wow, so it's really oil?! Bizarre. Do you know where I can find whale bone other Bolinas. I heard "Point Arena" has them. South of Pescadero Beaches?
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Fossilman
Cave Dweller
Member since January 2009
Posts: 20,723 
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Post by Fossilman on Apr 11, 2015 20:16:01 GMT -5
Nice score!!!!!!!!!!!!
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Post by stephan on Apr 13, 2015 13:59:28 GMT -5
Wow, so it's really oil?! Bizarre. Do you know where I can find whale bone other Bolinas. I heard "Point Arena" has them. South of Pescadero Beaches? Some people say it's oil or tar, others say it's the local black jasper (which has the incredibly politically incorrect name of "tar baby jasper"). Some agates there are pure black/brown, and don't seem to have any oil. www.flickr.com/photos/36618387@N06/3373971838/in/set-72157615637404335BTW, Point Arena is up in Mendocino, and has whale bone, but no oil agates that I'm aware of. And, yes, that beach seems picked over. I have the best luck looking under piles of seaweed, but most stuff seems quite small, even after a storm. |
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Post by gingerkid on Apr 13, 2015 17:09:26 GMT -5
I like your Tar Baby jasper, stephan. Interesting that it may be tar in the bolinas, and thanks for sharing with us.  |
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Bolinas
Apr 13, 2015 18:22:37 GMT -5
via mobile
Post by Deleted on Apr 13, 2015 18:22:37 GMT -5
To test for petroleum cut on water saw and have a sniff. Report back here.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,612
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Bolinas
Apr 13, 2015 18:34:12 GMT -5
Post by jamesp on Apr 13, 2015 18:34:12 GMT -5
Valdez agate-not funny
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Bolinas
Apr 14, 2015 10:16:49 GMT -5
Post by stephan on Apr 14, 2015 10:16:49 GMT -5
gingerkid: there are tar seeps in other places off the California coast, like Jalama Beach and other beaches of Santa Barbara County. I'm not aware of any this far north, but I suppose it is possible. Unlike Jalama, there are certainly no tarballs on beach.
shotgunner: Sorry, I'm not cutting the big one, and the oil agates I've found are too small to cut -- mostly <1/2 across. Maybe if I pick up another big one.... Personally, I think that oil agate was named for appearance, and that, over the years, people have taken the name too literally. It is probably manganese or hematite, similar Montana moss and other. I've not heard of any petroleum deposits in Marin county, and oil and agate form in such different ways, i just think that it is highly unlikely.
JMO
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Bolinas
Apr 14, 2015 10:17:52 GMT -5
Post by stephan on Apr 14, 2015 10:17:52 GMT -5
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,612
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Bolinas
Apr 14, 2015 10:24:49 GMT -5
kap likes this
Post by jamesp on Apr 14, 2015 10:24:49 GMT -5
Yes stephan, perhaps poor humor.... |
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Bolinas
Apr 14, 2015 10:49:55 GMT -5
Post by stephan on Apr 14, 2015 10:49:55 GMT -5
Yes stephan, perhaps poor humor.... Not at all. Just making sure that I was chuckling at the correct thing. I am a fan of gallows humor. |
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,612
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Post by jamesp on Apr 14, 2015 11:46:26 GMT -5
Yes stephan, perhaps poor humor.... Not at all. Just making sure that I was chuckling at the correct thing. I am a fan of gallows humor. My friend stephan, I will take any humor I can get. Seems like the alternative is not so good these days. |
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