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Post by 1dave on Nov 4, 2013 14:07:22 GMT -5
Here are some fill sequences to examine from Brazilian Amygduloids. a closer look: Another: And my favorite:
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Post by pghram on Nov 5, 2013 15:04:15 GMT -5
Great specimens, I'd be very tempted to cab the plumbs in the last one :>)
Rich
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Post by 1dave on Nov 13, 2013 12:09:14 GMT -5
I found the first example intriguing in that at one time quartz crystals grew, then the fluids heated up and melted the terminations, then the smoky cloud material entered. Far easier to interpret are planar layers that built from the bottom up. The sequences are easily verified by the "Tilt Egg" (a photo of this specimen was the picture of the day on Mindat.org back in June '13) that obviously filled, the dried out, the rock shifted slowly down on one side, repeated numerous times.
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Post by Deleted on Nov 13, 2013 14:07:44 GMT -5
Too many questions.
Why did they build bottom up and not concentric to the shell?
Different temperature?
Different solution/gel concentration?
Different gravity?
I have a smart friend who says that gravity changed after the concentric agate spheroids were formed. Who is to say he is wrong? What is gravity anyway?
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Post by Deleted on Nov 13, 2013 14:13:23 GMT -5
I found the first example intriguing in that at one time quartz crystals grew, then the fluids heated up and melted the terminations, Melted or re-dissolved?
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Post by Deleted on Nov 13, 2013 14:49:22 GMT -5
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Post by 1dave on Nov 13, 2013 15:13:44 GMT -5
I found the first example intriguing in that at one time quartz crystals grew, then the fluids heated up and melted the terminations, Melted or re-dissolved? Your termination is more accurate. It happens all the time as granite solidifies, crystallization generating heat and crystals going back into solution.
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panamark
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Post by panamark on Nov 13, 2013 15:41:46 GMT -5
Albert Einstein said gravity is a result of the curvature of space-time. Okay? The cause of gravity remains illusive, but the Higgs Boson particle is physicists' latest gasp. As for me, I will stick to rocks. They are simpler to understand.
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Post by wireholic on Nov 13, 2013 17:50:22 GMT -5
Albert Einstein said gravity is a result of the curvature of space-time. Okay? The cause of gravity remains illusive, but the Higgs Boson particle is physicists' latest gasp. As for me, I will stick to rocks. They are simpler to understand. Gravity is what keeps all those rocks stuck to the ground!
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Post by Deleted on Nov 13, 2013 19:17:29 GMT -5
Old people should live on the moon where rocks are not so heavy. Jim
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Post by Deleted on Nov 13, 2013 19:22:39 GMT -5
Dave, had you ever seen a geode with stalactites before? The progression of that formation is pretty amazing. Jim
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Post by wireholic on Nov 13, 2013 19:33:49 GMT -5
I've often wondered what the inside of stalagtite & stalagmites looked like.
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Post by Deleted on Nov 13, 2013 19:43:31 GMT -5
Hi Karen - here is the inside of a calcite based stalagtite The last one shows the growth layers best. This is a hunk of kokoweef material. This is a privately owned cave that the owners are exploring extensively for a " river of gold". If you ever see rhodocrosite with lots of circles or concentric rings, that is a stalagtite of rhodochrosite.
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Post by Deleted on Nov 13, 2013 19:54:24 GMT -5
Those are pretty large. Did you make spheres out of them? Jim
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Post by Deleted on Nov 13, 2013 23:41:24 GMT -5
That is one 4-5" cube I WILL sphere up when I get myself back on track. Soccer is over for a few months now. Life becoming my own again.
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Post by 1dave on Nov 14, 2013 8:59:41 GMT -5
Dave, had you ever seen a geode with stalactites before? The progression of that formation is pretty amazing. Jim Yes, These were later coated with quartz crystals. The Geode Kid calls them "Angel Wings." Stalactites grew in many rock cavities, then were embedded in new material before we came on the scene to enjoy them. We find them in slices from time to time. Most folks call hollow thundereggs duds. I find them very informative! There are boulders full of them around Richardson Ranch, Madras Oregon. They must have been above the water table when the fill sequences began.
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Post by Deleted on Nov 14, 2013 10:46:29 GMT -5
That is way cooler than mine. Beautiful times ten. Jim
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Post by Deleted on Nov 14, 2013 15:25:34 GMT -5
There are boulders full of them around Richardson Ranch, Madras Oregon. They must have been above the water table when the fill sequences began. Interestingly, I think the Geode Kid described the hollow ones as being closer to the surface of the perlite layer. Found it:
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Post by Deleted on Nov 14, 2013 15:57:49 GMT -5
Very interesting. I wonder why my geode has stalactites that do not have crystals. mine only has crystals on the bottom and the rest of it is like calcium deposits on a sink or faucet. I am afraid to put it in acid because it might totally destroy them. I broke off a little spot where it is hard to see and they look the same all the way through. Maybe there was hard city water running through it. Jim
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Post by 1dave on Nov 14, 2013 20:27:57 GMT -5
@wampidy "I wonder why my geode has stalactites that do not have crystals."
Thunderegg environment is constantly changing as fill takes place. Groundwater levels rising and falling, minerals in solution changing, earthquakes, landslides, volcanic eruptions, geysers pulsating the groundwater, temperatures and pressures rising and falling . . .
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