jamesp
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Post by jamesp on Nov 2, 2013 10:06:57 GMT -5
I have this fresnal lens Bill. It was made to put in front of a TV to make the image larger back in the old days. Used to melt my lead to make fishing sinkers w/it. Edmund Scientific used to sell a 41" x 41" and plans to mount it like the fellow in the video. Rated at 3000F. That's bloody hot. I think this furnace is 9 of them Light houses use fresnals. Most are several inches thick. Most have bullet hits in them. It is an old science .
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jamesp
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Post by jamesp on Nov 2, 2013 10:13:14 GMT -5
Look at these that cracked and the resislicified. I see this all the time. Center of photo in particular
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jamesp
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Post by jamesp on Nov 2, 2013 10:15:14 GMT -5
Maybe in, oh, about 100,000 years? I would assume time has to figure into the equation somehow. It is my opinion that is doesn't take 100,000 years to make agates. I't is my rather unqualified yet humble opinion that that layered agates are one rainy season per layer. Thinner layers in places where there was less rain when they formed. If, because rain dissolved it all away, additional alkali is needed to complete the stone, then we must wait for an event to supply that alkali. THAT, then could make us wait 100,000 years or more for the process to complete. Forest fires have come to mind since we discussed this in relation to Jim's coral. The chemistry described by dave is exactly the chemistry I am using for synth-agates. Also, there is evidence that some agates are as much half carbonates. The plumes being calcite/aragonite. See above photo
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jamesp
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Post by jamesp on Nov 2, 2013 11:36:58 GMT -5
Here is a 2 cavity that can be compared. Notice the left changed position and caused formations to follow gravity (most likely).Telling us that the right side formed and hardened first. This one broke and then got drusified A few more and some geological theory and some wild prices www.paleodirect.com/coral1.htm
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jamesp
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Post by jamesp on Nov 2, 2013 11:51:56 GMT -5
Scott, i am all ears. I have been collecting fossilized/silicified stuff for years. I see it the size of cars. I would not be surprised if you found a whole silicified whale down here. Half of the gravel in Florida is crushed chert of fossiliferous nature. You may look at optical glass. It is some of the finest glass in the world. Try this
Flint glass noun Optics. an optical glass of high dispersion and a relatively high index of refraction, composed of alkalis, lead oxide, and silica, with or without other bases, sometimes used as the diverging lens component of an achromatic lens. Origin: 1665–75
I think it is one of those God secrets. If you told a lens maker he could make an objective lens w/mohs 7 he would be your dear friend. What differentiates glass from agate?
Why does 600F turn the chertiest, toughest coral into a material that chips like the softest of glass. Sure makes spearpoint manufacture easy and it sure is a temperature friendly process w/3 inches of soil and a camp fire on top.
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Post by 1dave on Nov 2, 2013 14:44:58 GMT -5
I think so many of those dissolved silica reactions do take for ever. I have dug agate that I had to let dry before picking up or it would crumble to pieces. In an hour it was fine. H 2O and SiO 2 react much the same with their transition points. Chalcedony seems to form around 50 degrees C. I'll have to find the article about how Brazilian Cathedral agate is formed. As I recall, millions of years ago lava flowed across a limestone lake bed, CO 2 gas made the tubes, more millions of years passed, then groundwater around 40-50 0C entered and began depositing first green (celedonite?) layers, then layers of chalcedony, then at a cooler temperature, the horizontal layers, but things warmed up periodically and prior layers melted, then started layering again. When Silica hits 273 degrees C, Low Quartz (3 point terminations) begin growing. Above 573 degrees C, High quartz (6 point terminations) are formed instead. cool below that, and the external structure remains the same - with perhaps a few stress fractures, but internally it is now low quartz. It is similar to those ice cubes crackling when you drop them in a glass of water, but they are warming up from one phase to the next. So we can look at a geode and determine the order and temperatures the layers and crystals formed in. I visited Texas Instruments in Houston when they first began making transistors. They gave up on natural crystals and began growing their own. It took weeks, not billions of years! This conversation really should be in a thread of it's own. Dave
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jamesp
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Post by jamesp on Nov 2, 2013 18:38:52 GMT -5
The chalcedony is the interesting one if it forms at such a low temp . That is all too interesting. I know that ground water and limestone can cause silica deposits. But it may be from a slow leaching effect. Or deposited over a long term leaching effect.
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Deleted
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Post by Deleted on Nov 2, 2013 19:21:54 GMT -5
Here is a 2 cavity that can be compared. Notice the left changed position and caused formations to follow gravity (most likely).Telling us that the right side formed and hardened first. This one broke and then got drusified A few more and some geological theory and some wild prices www.paleodirect.com/coral1.htm[/quote Holly Molly James, by the looks of those prices you must have half a million bucks sitting there. Maybe you need to get a large walk in save. That stuff must be as valuable as silver by weight. Jim
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jamesp
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Post by jamesp on Nov 2, 2013 20:08:06 GMT -5
Those photos are 'Paleodirect' website. Nothing to do with me Jim. But i do have a lot of those psuedomorphs. I don't care for them that much. Guess i should concentrate on collecting them w/those $$$$.
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quartz
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Post by quartz on Nov 2, 2013 22:18:16 GMT -5
MSRP & actual selling price often vary greatly.
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jamesp
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Post by jamesp on Nov 5, 2013 22:56:02 GMT -5
yea. Tell me about it
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jamesp
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Post by jamesp on Nov 6, 2013 14:24:03 GMT -5
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Deleted
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Post by Deleted on Nov 8, 2013 13:44:37 GMT -5
those are so freekin' nice.
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Post by rockpickerforever on Nov 8, 2013 13:57:44 GMT -5
Awesome colors, James!
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quartz
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Post by quartz on Nov 8, 2013 14:05:34 GMT -5
Rock [eye] candy for sure.
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jamesp
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Post by jamesp on Nov 8, 2013 15:40:32 GMT -5
It a weird thing to do to a rock. I am mesmerized at this peculiar process. It appears that higher temps are doable if you really really dry the stuff out. But any moisture leaves a fractured mess.
A good thing to have is an oven that is well insulated and can hold 180-200F for a long time for drying. And then one you can take up to a solid 600F for most rocks.
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Fossilman
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Post by Fossilman on Nov 8, 2013 16:56:30 GMT -5
Awesome! That should work great! Just had a thought,we use to heat crude oil with "Hot Oil Trucks",they had a diesel coil system on the main burner for heating the oil.Temps would heat faster with water,so a quicker and faster heat.... I wonder if a guy could use the coil system in its own chamber to heat rocks,if I layered the floor of the tube with sand..... I know where to pick them up in ND,they are a dime a dozen now. Every company switched to propane coils and burners.... Those old burners could cook up to 800 degrees F........
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