Rogue Trader
freely admits to licking rocks
"Don't cry because you are leaving, smile because you were there."
Member since December 2008
Posts: 839
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Post by Rogue Trader on Jan 16, 2009 15:40:58 GMT -5
 I'm thinking of going hounding at a site that is predominantly Limestone. Is this a good idea? What (apart from limestone, chert/flint) am I likely to find?
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Sabre52
Cave Dweller 
Me and my gal, Rosie
Member since August 2005
Posts: 20,497
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Post by Sabre52 on Jan 16, 2009 16:07:27 GMT -5
Howdy Rogue, We're all limestone around here. Like you've said, lots of chert and flint but then chert and flint can look like a lot of other materials and be pretty darn nice solid material. Especially if you watch for the banded or orby specimens. Another thing I always watch for is polishible limestone with good looking fossils. Lots of the limestone just east of here is fantastic stuff full of crinoids and brachiopods. Makes cool gemstones. Other things to watch for are flint nodules with fossils included and psuedomorphs where fossils have been replaced by silica. There are also some fine druzes in flint nodules sometimes and often limestone can contain sedimentary agate such as Fairburns, Kentuckys, Dryheads, and Tee Pees. Crazy Lace agate comes from limestone as does Missouri Lace and several other agate types...Mel
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Post by Jack, lapidaryrough on Jan 16, 2009 16:47:44 GMT -5
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navi
starting to spend too much on rocks
Member since November 2008
Posts: 229
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Post by navi on Jan 18, 2009 10:21:33 GMT -5
i've only seen missouri lace in a volcanic type rock. you know somewhere i dont? do tell, i want to go.
as for limestone, 'round here is fossils, calcite, dolomite, barrite, galena, and vugs of quartz crystals, up to about 3/8" in diameter.
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,497
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Post by Sabre52 on Jan 25, 2009 10:55:09 GMT -5
Hmm. I can only go by what the books say as I've never hunted Missouri lace myself but the books say the host rock for that material is Potosi dolomite (Calcium magnesium carbonate) which is not limestone ( calcium carbonate) so I was incorrect but definitely not volcanic either *S*. Missouri lace is a sedimentary agate in the chert group I think.....Mel
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NDK
Cave Dweller
Member since January 2009
Posts: 9,440
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Post by NDK on Jan 26, 2009 22:08:09 GMT -5
I seem to have all limestone here locally too. What would chert, flint, or the agates mentioned look like in the limestone? Would it be in a vein, or like stones imbeded in the limestone?
Thanks
Nate
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Slydog
has rocks in the head
Member since February 2006
Posts: 555
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Post by Slydog on Jan 26, 2009 22:43:35 GMT -5
Don't get too excited, Nate. Once summer came, I was going to clue you in on a good fossil place, but we need to wait till the creek there dries up. Never found anything polishable there, just fossils, but they are pretty cool to find. You won't find agates or anything. But it sure beats sitting home wishing you could go rockhunting!
Nona
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,497
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Post by Sabre52 on Jan 26, 2009 22:50:02 GMT -5
Nate: I'm not sure all limestone deposits have a lot of flint and chert but you should have some at least. We have the Edwards Limestone here locally and the flint and chert occurs both as veins and as white or yellow crusted nodules. The agates can occur as veins or nodules too. They occur in place in the host rock and loose in the soil or on gravel beds along streams. The quartz gems are very hard and the limestone is softer and erodes away so I'd check local gravel beds or rocky hillsides and you should find some material....Mel
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Slydog
has rocks in the head
Member since February 2006
Posts: 555
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Post by Slydog on Jan 26, 2009 23:27:10 GMT -5
Hi Mel, this will be part of the Niagara Escarpment, all soft limestone in this area. You can make clay creatures out of the stuff if it is wet. Been going there since I was a little kid. I honestly have never seen anything else besides the fossils worth picking up. Almost everything in WI is private land, as is the top of this streambed. I've checked it's sides many times. I'll triple check this year, just in case I missed anything  Nona |
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,497
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Post by Sabre52 on Jan 27, 2009 9:37:45 GMT -5
Nona: Yeah, I guess some limestone is quartz free. I know the silica in limestone is often biogenic requiring an overlaying layer of diatomaceous earth, radiolarian ooze or sponge spicules to provide the silica for the flint or chert. Maybe none of those conditions are met in your area so there is no silica source to build quartz gems....Mel
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NDK
Cave Dweller
Member since January 2009
Posts: 9,440
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Post by NDK on Jan 27, 2009 23:14:35 GMT -5
I wasn't expecting to necessarily find anything in the local limestone. I just was more interested in how it would be formed in it. Thanks for the explination, Mel.
And thank you, too, Nona for the head's up. There's a large cliff, or wall, of limestone starting 1/2 mile from where I grew up, and it runs for a good 3/4 mile. I was hoping maybe I could find something worth collecting there. But yeah, it's all private land, and I don't know if they'd allow hounding. I guess if there was anything worth collecting it would be picked apart by now.
But hey, you can't blame a guy for dreaming, right?
Nate
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Nov 15, 2024 17:44:51 GMT -5
Nov 15, 2024 17:44:51 GMT -5
