|
|
Post by hummingbirdstones on Sept 14, 2021 9:52:25 GMT -5
holajonathan - Dang! Those are some more amazing slabs! That last one...I see that "measles" look to a lot of Teepee Canyon Agates...interesting... The "measles" look is a good description. I've seen the same in other agates, such as Botswana agates and Lake Superior Agates. I don't know if the red specks have a name or what cause them. I wonder if 1dave knows? He seems to know more than most about such matters. The scientific name for them are speckles, at least in my book.  |
|
|
|
Post by jasoninsd on Sept 14, 2021 10:11:08 GMT -5
The "measles" look is a good description. I've seen the same in other agates, such as Botswana agates and Lake Superior Agates. I don't know if the red specks have a name or what cause them. I wonder if 1dave knows? He seems to know more than most about such matters. The scientific name for them are speckles, at least in my book. I think you and I read the same "scientific journals"...as I've found the technical name for a LOT of things to be whatchamcallits!  |
|
|
|
Post by holajonathan on Sept 14, 2021 21:04:18 GMT -5
Adding this here for archival purposes:  |
|
|
|
Post by 1dave on Sept 14, 2021 21:55:46 GMT -5
Thanks for sharing the Rhythmic Banding!  |
|
|
|
Post by 1dave on Sept 14, 2021 22:23:00 GMT -5
holajonathan - Dang! Those are some more amazing slabs! That last one...I see that "measles" look to a lot of Teepee Canyon Agates...interesting... The "measles" look is a good description. I've seen the same in other agates, such as Botswana agates and Lake Superior Agates. I don't know if the red specks have a name or what cause them. I wonder if 1dave knows? He seems to know more than most about such matters. I have a weird/wild theory, but first a word from my sponsors:   My theory: Billions of tons of iron meteorites rain down every day. Most turn to "black sand.' Some get caught up in ground water and enter cavities to become part of agates, jaspers, etc. The theory may be wrong, . . . . but It's MINE! |
|
|
|
Post by 1dave on Sept 14, 2021 22:34:05 GMT -5
Slabbing the lace agates is equal parts thrilling and heartbreaking. On the one hand, they always look amazing when pulled off the saw, dripping with oil. And when washed and dried, they always have fractures. It's an emotional rollercoaster. I've got to figure out an economical way to stabilize some of these slabs. The smaller, almost complete nodules (like the 1st and 8th photos I posted) usually have amazing patters, but they also have the most cracks and soft spots. I say "economical way to stabilize" because I'm not paying $80 an ounce, or whatever some of the fancy stabilizers cost, to treat pounds of crazy lace slabs. But if the epoxy / acetone methods I've read about work well, that might be a viable option. Maybe try the the method fencejumper posted. |
|
|
|
Post by holajonathan on Sept 14, 2021 22:43:17 GMT -5
1dave Well, it's a theory, and the only we've got at the moment. But I think you can do better.  I am always curious when I see recurring peculiarities in rocks from diverse geographic origins. In nodular agates, the red specs often show show up in a thin chalcedony layer that separates banded chalcedony from macro quartz. That seems to be a clue -- that they form during a transitional period when the dissolved silica level in the water is dropping? Could it be that something about the structure or formation of crystals at a certain silica concentration permits or facilitates the incorporation of iron into the crystal matrix? Way, way, above my pay grade, but it gives me something to think about other than magic ferry meteorite dust.
|
|
|
|
Post by holajonathan on Sept 14, 2021 22:47:57 GMT -5
1dave Are you endorsing the Cactus Juice? Is your meteorite theory brought to us compliments of Cactus Juice? 
|
|
|
|
Post by 1dave on Sept 14, 2021 23:32:33 GMT -5
1dave Well, it's a theory, and the only we've got at the moment. But I think you can do better. I am always curious when I see recurring peculiarities in rocks from diverse geographic origins. In nodular agates, the red specs often show show up in a thin chalcedony layer that separates banded chalcedony from macro quartz. That seems to be a clue -- that they form during a transitional period when the dissolved silica level in the water is dropping? Could it be that something about the structure or formation of crystals at a certain silica concentration permits or facilitates the incorporation of iron into the crystal matrix? Way, way, above my pay grade, but it gives me something to think about other than magic ferry meteorite dust. Try these:  forum.rocktumblinghobby.com/post/1094252/threadforum.rocktumblinghobby.com/post/1133807/thread |
|
|
|
Post by holajonathan on Sept 15, 2021 10:30:09 GMT -5
1dave Well, it's a theory, and the only we've got at the moment. But I think you can do better. I am always curious when I see recurring peculiarities in rocks from diverse geographic origins. In nodular agates, the red specs often show show up in a thin chalcedony layer that separates banded chalcedony from macro quartz. That seems to be a clue -- that they form during a transitional period when the dissolved silica level in the water is dropping? Could it be that something about the structure or formation of crystals at a certain silica concentration permits or facilitates the incorporation of iron into the crystal matrix? Way, way, above my pay grade, but it gives me something to think about other than magic ferry meteorite dust. Try these: forum.rocktumblinghobby.com/post/1094252/threadforum.rocktumblinghobby.com/post/1133807/threadThe information in the first thread is directly on point. It suggests there is something to my observation about iron (hematite) inclusions forming in transitional areas of the crystal strands. I will gather up all the rocks I can find in my collection that seem to exhibit this phenomenon, photograph them, and post them to that thread. I'm sure others have many examples also. I recall jamesp posting many agate photos with bright red specs. He had a name for them... something like "spice." Thank you for providing a good starting point for my very amateur inquiry. |
|
|
|
Post by 1dave on Sept 15, 2021 11:35:22 GMT -5
The information in the first thread is directly on point. It suggests there is something to my observation about iron (hematite) inclusions forming in transitional areas of the crystal strands. I will gather up all the rocks I can find in my collection that seem to exhibit this phenomenon, photograph them, and post them to that thread. I'm sure others have many examples also. I recall jamesp posting many agate photos with bright red specs. He had a name for them... something like "spice." Thank you for providing a good starting point for my very amateur inquiry. & n b s p thanks you.   As mantle magma (Olivine) melts the high silica rocks above, it slowly changes to Basalt, Andesite, Dacite, Obsidian and Rhyolite. At those high temperatures electrons are running wild! At ~ 1,100 oC SiO 2 molecules line up in long magnetic needles we call cristobalite. Those needles are attracted to tiny IRON MOLECULES (cinders of tiny meteorites?) and begin forming puff-balls, the beginnings of spheroids that may grow into Thundereggs. That is what happens at high temperatures.
Not much happens at absolute zero, but as stuff warms up (heat is stored in the nucleus causing it to vibrate harder and harder) electrons traveling at hundreds of thousands of miles per SECOND are kicked out of inner orbits, kicking more distant electrons out of their orbits. So even at low temperatures, oxygen bonds lengthen, then silicon bonds lengthen . . . The sizes of bricks keep changing on a quantum basis. After so many changes, the pattern repeats itself. Opal, Tridymite, Cristobalite, Chalcedony, Moganite, Quartz. The cavity dries up. Repeat, repeat, repeat. If tiny bits of iron are present, little puff-balls appear and in extended periods can get quite large. In narrow spaces chalcedony needles colored by whatever attach to both sidewalls, repeat, repeat, repeat - Rhythmic Banding. If large chunks of iron is present, large red, yellow, or green spots will appear depending on how many electrons happen to be in the iron outer shell. Other minerals produce a variety of colors. |
|
|
|
Post by holajonathan on Sept 28, 2021 16:03:44 GMT -5
|
|
|
|
Post by holajonathan on Oct 4, 2021 0:22:21 GMT -5
|
|
|
|
Post by knave on Oct 4, 2021 5:24:54 GMT -5
Love the chubby little hexagon!
|
|
|
|
Post by stephan on Oct 10, 2021 22:39:06 GMT -5
The "measles" look is a good description. I've seen the same in other agates, such as Botswana agates and Lake Superior Agates. I don't know if the red specks have a name or what cause them. I wonder if 1dave knows? He seems to know more than most about such matters. The scientific name for them are speckles, at least in my book. I always thought it was “awesome speckles.” Maybe that’s just me. I have a weakness for them. |
|
|
|
Post by stephan on Oct 10, 2021 22:56:28 GMT -5
The information in the first thread is directly on point. It suggests there is something to my observation about iron (hematite) inclusions forming in transitional areas of the crystal strands. I will gather up all the rocks I can find in my collection that seem to exhibit this phenomenon, photograph them, and post them to that thread. I'm sure others have many examples also. I recall jamesp posting many agate photos with bright red specs. He had a name for them... something like "spice." Thank you for providing a good starting point for my very amateur inquiry. & n b s p thanks you. As mantle magma (Olivine) melts the high silica rocks above, it slowly changes to Basalt, Andesite, Dacite, Obsidian and Rhyolite. At those high temperatures electrons are running wild! At ~ 1,100 oC SiO 2 molecules line up in long magnetic needles we call cristobalite. Those needles are attracted to tiny IRON MOLECULES (cinders of tiny meteorites?) and begin forming puff-balls, the beginnings of spheroids that may grow into Thundereggs. That is what happens at high temperatures.
Not much happens at absolute zero, but as stuff warms up (heat is stored in the nucleus causing it to vibrate harder and harder) electrons traveling at hundreds of thousands of miles per SECOND are kicked out of inner orbits, kicking more distant electrons out of their orbits. So even at low temperatures, oxygen bonds lengthen, then silicon bonds lengthen . . . The sizes of bricks keep changing on a quantum basis. After so many changes, the pattern repeats itself. Opal, Tridymite, Cristobalite, Chalcedony, Moganite, Quartz. The cavity dries up. Repeat, repeat, repeat. If tiny bits of iron are present, little puff-balls appear and in extended periods can get quite large. In narrow spaces chalcedony needles colored by whatever attach to both sidewalls, repeat, repeat, repeat - Rhythmic Banding. If large chunks of iron is present, large red, yellow, or green spots will appear depending on how many electrons happen to be in the iron outer shell. Other minerals produce a variety of colors. Iron can occur as Fe 2+ or Fe 3+. The other factor that influences color is the counter-ion (Cl -, O 2-, OH -, SO 42-, being some common ones, sometimes in combinations). Iron is probably the most common metal lending color to agates and jaspers. |
|
|
|
Post by stephan on Oct 10, 2021 23:01:33 GMT -5
It appears I’ve been neglecting my thread for a while, so here is a Laguna Lace made from a slab I received in trade with holajonathan :  DSC_0596_Laguna lace agate by Stephan T., on Flickr It has some really nice parallax/shadow agate, and also a couple of druzy caves and some sagenite! The trade was a little lopsided; it’s really more of a gift. The picture is a little over-exposed. I’ll try to retake it, but the mirror polish this took isn’t helping.  This stuff was hard and solid, in spite of USPS using it for target practice before delivering it. (I thought I heard someone yell, “pull!”) |
|
|
|
Post by holajonathan on Oct 10, 2021 23:48:43 GMT -5
It appears I’ve been neglecting my thread for a while, so here is a Laguna Lace made from a slab I received in trade with holajonathan :  DSC_0596_Laguna lace agate by sdttds, on Flickr It has some really nice parallax/shadow agate, and also a couple of druzy caves and some sagenite! The trade was a little lopsided; it’s really more of a gift. The picture is a little over-exposed. I’ll try to retake it, but the mirror polish this took isn’t helping. This stuff was hard and solid, in spite of USPS using it for target practice before delivering it. (I thought I heard someone yell, “pull!”) Wow, you nailed that one, Stephan. One of the better Mexican lace cabs you've posted, I'd say. Great composition with the quartz running through the center, dividing the different color banding on both sides. I'm glad you're liking the material. I'm looking forward to cabbing more of the slabs you sent me, but I'm in the process of converting my trim saw from oil to water, so I can use it more often without taking an oil shower. The rainbow calcite was soft enough that I scored it with a carbide box cutter and gently tapped it against a wooden table. 30 second preform! The other slabs you sent me actually need cut as soon as I get my trim saw running on water. It has 5 gallons of dirty oil in it right now, and I've got to be in a special mood to want to deal with that. Back to your cab -- you pulled in the most appealing (and most challenging) features of the slab: the fine banding (often fractured / unstable), quartz (often soft or unstable), and druzy vugs (easy to over grind). I can't see the sagenite in the scaled down photo, but I'll check out the full size image on Flickr. |
|
|
|
Post by holajonathan on Oct 10, 2021 23:54:32 GMT -5
stephanYou should consider increasing the photo size when you post through the forum. I think there's a setting for that, right? The larger photo on Flickr shows the fine banding so much better. I'm not suggesting you post huge photos to the forum. That is, indeed, disruptive. But might you consider bumping the size just a little?
|
|
gemfeller
Cave Dweller 
Member since June 2011
Posts: 4,074 
Member is Online
|
Post by gemfeller on Oct 11, 2021 1:40:04 GMT -5
It's been a while since I posted to this thread. I don't know if Crown of Silver Psilomelane is technically an agate but it's certainly heavily impregnated with SiO2. Some variations even have drusy quartz vugs. This however is an example of one of the finer non-vuggy patterned cabs I've cut.  |
|
