kbrocks
noticing nice landscape pebbles
Member since September 2006
Posts: 78
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Post by kbrocks on Aug 19, 2008 11:07:32 GMT -5
Well, life's been busy and I've been AWOL for a while. I'm back to it now, both hunting and tumbling.
So, I've got an ID question, and for the time being have no pic to post (at work, but will hopefully put one up later).
Anyway, we went to San Antonio to visit family and do some house hunting for our hopefully soon relocation back. I decided to take my girls to McAllister park in NE San Antonio. After straying a few feet off the path, I found a really nice agate. I'll describe it as best I can.
It is mostly round and grapefruit sized. The outside is light colored, white-ish and gray. I assumed agate because there were pockets of the bubbly agate features on it.
Well, I shoved it in my suitcase and when I got home I left it alone,....for a while. Curiosity got the better of me so I broke out the hammer and whacked it. I was able to knock off some good peices without messing up the whole stone. The inside is a little cloudy, almost clear but a little like dirty tap water. I can make out what look like tan and brown plumes and some white plumes in it.
As far as I know, Texas doesn't have a huge variety of agates, and judging by location, does anyone care to guess without seeing the pics?
I'll put picks up ASAP.
Thanks
Oh, also. I've checked some sites, Woodward Ranch, AgatesWithInclusions, and a few others. I haven't found any exact matches, but I've seen a couple Marfa Agates that look similar. If that helps.
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,463
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Post by Sabre52 on Aug 19, 2008 15:11:24 GMT -5
Actually, Texas is one of the main agate producing states but true agates are mainly in the volcanics of West Texas. I think sedimentary rocks are the standard around San Antonio so true agates are not really to be expected however, silica from radiolarians etc often fills voids in the local limestones creating what is usually termed flint. That being said though, translucent or transparent flint is, for all intents and purposes, about the same as the chalcedony that makes up agates. Both are basically microcrystalline quartz. I've seen flint with bands, fortifications, geodes etc just like agate and the famous Fairburns, Prairies, Dryheads, Kentucky and Teepee Canyon specimens which are classed as agate come from limestone deposits. So, what you've found is probably a sedimentary flint nodule but chemistrywise it's not much different than a non banded form of agate....Mel
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kbrocks
noticing nice landscape pebbles
Member since September 2006
Posts: 78
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Post by kbrocks on Aug 19, 2008 18:33:31 GMT -5
Ok, pics as promised. I didn't upload any exterior shots, but can if needed. The outside does resemble some of the flint nodules I've found in the past, but if it is a flint variety, it's one I haven't seen. Also, it's broken into 3 pieces, not including what's in the tumbler now. On the largest piece, There are 2 very small hollow cavities that have a crystal like structure growing within them, the one on the right is white and the one on the left looks almost orange. Also, there are small white bubbles within the clearish parts. Very interesting looking to me. Pics are clickable.
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,463
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Post by Sabre52 on Aug 20, 2008 18:34:17 GMT -5
Yeah, I'd still call them flint and those oolitic spheroids do sometimes occur in such material. The spheres are also common in South Dakota's Prairie and Bubble gum agate which are again from sedimentary deposits and often resemble flint nodules....Mel
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kbrocks
noticing nice landscape pebbles
Member since September 2006
Posts: 78
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Post by kbrocks on Aug 21, 2008 7:38:53 GMT -5
Cool.. Thanks for the ID. I learn something new everyday. I do have a lot of West/Central Texas flint, I had just never seen one that was all clear or cloudy like that. A lot of the nodules I have are a variation of brown or black, and many of them have clearish bubbles in them. Honestly, I really like working with the flint. For me, it takes a really good shine, and if I can break them just right they look even better. <<still no saw, using the hammer.
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