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Post by fernwood on Sept 7, 2019 5:18:13 GMT -5
I recently received a bag of AZ Fire Agates. Have never seen any in person before, so lots of questions.
Is there a way to determine if there "may" be fire/bubbles in them? I set some of them on top of a high power flashlight. Checked all sides. Saw some bubbles and fire. Is there a better way to do this?
Read that this material is 6-7 hardness. Also read that the areas of fire are often very thin and disappear if they are overworked.
Is it all trial and error to determine how far is far enough to go?
I do not want to mess these up, so thanks for any advice.
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Fossilman
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Post by Fossilman on Sept 7, 2019 9:09:38 GMT -5
Fire agate, easy to burn the fire out! Just start grinding the stone, checking it often (After a few stones, you will know if it has fire, just by looking at it) - The fire will appear... A few people on here do this professionally and are good at it... I just mess around with it for enjoyment! Good luck on the adventure of fire!
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Post by rmf on Sept 7, 2019 9:18:49 GMT -5
Throwing them in the tumbler and tumbling to get a good shine will sometimes bring out the "fire" which is water trapped in the structure (botryoidal) of the chalcedony. Some can be ground out like a typical cab and some fire follows the bubbles such that if you finish like a cab you loose (grind away) all the fire.
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Post by fernwood on Sept 8, 2019 3:34:00 GMT -5
Thanks for the info. Here is a sample of what I received.
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hummingbirdstones2
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Post by hummingbirdstones2 on Sept 8, 2019 11:15:59 GMT -5
Take 'em outside on a sunny day. Spray them or dunk them in water. Turn your back to the sun and look at them from all angles with the sun coming directly over your shoulder. The closer the stone is to being lined up with the shadow of your head, the better it is. When you, the sun, and the stone are all in line there's less chance of missing some color that might be showing at a different angle.
A really bright light will work, but sunlight always seems to be the best. Same process for opal, obsidian, or any chatoyant stone.
Good luck!
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Post by jasoninsd on Dec 28, 2020 8:09:13 GMT -5
fernwood - I ran across this thread last night after searching for Fire Opal. I was curious if you had any results (positive or negative) with working this material - or if you had a chance to work it yet? I got curious about the material after I saw some rough for sale online.
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Post by fernwood on Dec 28, 2020 8:19:23 GMT -5
fernwood - I ran across this thread last night after searching for Fire Opal. I was curious if you had any results (positive or negative) with working this material - or if you had a chance to work it yet? I got curious about the material after I saw some rough for sale online. I will try to find the photos of some I tumbled.
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Post by jasoninsd on Dec 28, 2020 8:24:19 GMT -5
fernwood - I ran across this thread last night after searching for Fire Opal. I was curious if you had any results (positive or negative) with working this material - or if you had a chance to work it yet? I got curious about the material after I saw some rough for sale online. I will try to find the photos of some I tumbled. I was wondering if you had tumbled them or tried to grind them down by hand...well, by hand tool...if really done by hand, you'd probably still be at it and have a lot shorter fingernails! Thanks for searching for the photos...I really am curious.
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Post by greig on Dec 28, 2020 13:37:46 GMT -5
I have never played with fire agate but have found that rough moonstone sometimes gives off its glow best in the dark when wet, from a short distance with a strong light (looking from one or more directions). The concept might be the same and costs nothing to try.
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gemfeller
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Post by gemfeller on Dec 28, 2020 14:19:53 GMT -5
Take 'em outside on a sunny day. Spray them or dunk them in water. Turn your back to the sun and look at them from all angles with the sun coming directly over your shoulder. The closer the stone is to being lined up with the shadow of your head, the better it is. When you, the sun, and the stone are all in line there's less chance of missing some color that might be showing at a different angle.
A really bright light will work, but sunlight always seems to be the best. Same process for opal, obsidian, or any chatoyant stone.
Good luck!
fernwood Excellent advice! I've cut hundreds of fire agate cabs and it's not an easy stone. In fact it's the most challenging material I've ever worked with. But everyone has to start somewhere. My strongest advice is not to rush to the grinder. Learn all you can by other means before you even start. There are lots of YouTube videos that will help you. Check out the ones by Mark Ruiz in particular. I wrote an article many years ago about the procedure and I'd be happy to share it with you if you'll PM me your email so I can send it as an attachment. It covers mainly the cabbing approach but carving is explained in Mark's and other videos.
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Post by stephan on Dec 28, 2020 23:53:41 GMT -5
Throwing them in the tumbler and tumbling to get a good shine will sometimes bring out the "fire" which is water trapped in the structure (botryoidal) of the chalcedony. Some can be ground out like a typical cab and some fire follows the bubbles such that if you finish like a cab you loose (grind away) all the fire. I thought the fire was limonite.
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gemfeller
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Post by gemfeller on Dec 29, 2020 1:46:28 GMT -5
Throwing them in the tumbler and tumbling to get a good shine will sometimes bring out the "fire" which is water trapped in the structure (botryoidal) of the chalcedony. Some can be ground out like a typical cab and some fire follows the bubbles such that if you finish like a cab you loose (grind away) all the fire. I thought the fire was limonite. stephan , Close but it's actually another iron mineral, goethite. I disagree with tumbling fire agate rough. It can ruin some of the best gems if they're exposed on the surface. The iridescent layer is often just microns thick. This image shows a couple of rough stones with such sections that I gently polished as examples. They’ll make excellent cabs just by trim-sawing them and doing a bit of finish grinding/sanding.
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Post by fernwood on Dec 29, 2020 4:59:08 GMT -5
jasoninsd Here are the only photos I could find. The fire agates were in a very mixed load. I added some other, mostly white with flash rocks. Dunno if those would be considered fire agates or not. Before After 2 weeks in 60/90 SIC I did find the labeled bag that has this load in it. Agates, jasper, fire agates, misc. 1 month in 60/90. Needs more time in rough. Once my present loads are done, I think I will put these back in.
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Post by jasoninsd on Dec 29, 2020 6:28:25 GMT -5
fernwood - thank you so much for posting those pics. I'm glad you found the "hidden gem" of that bag of rough...and I look forward to seeing the finished tumble (if you don't mind posting pics of course ). I'm really curious to see if there will be any "fire" in the finished product. gemfeller - thank you so much for emailing me that paper. I read it with extreme interest. The picture you posted of those two are stunning! I am curious...is there a difference between Fire Agate and Fire Opal? I'm assuming if there is a difference, the procedure you outlined in the paper would be the same. I'm also betting the same technique you described with using the edge of the sanding belt could be transferred over to the EZ Lock sanding disks on a dremel. I found I can use the outer edge of the disks which will "contour" with the stone...
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gemfeller
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Post by gemfeller on Dec 29, 2020 10:22:03 GMT -5
fernwood - thank you so much for posting those pics. I'm glad you found the "hidden gem" of that bag of rough...and I look forward to seeing the finished tumble (if you don't mind posting pics of course ). I'm really curious to see if there will be any "fire" in the finished product. gemfeller - thank you so much for emailing me that paper. I read it with extreme interest. The picture you posted of those two are stunning! I am curious...is there a difference between Fire Agate and Fire Opal? I'm assuming if there is a difference, the procedure you outlined in the paper would be the same. I'm also betting the same technique you described with using the edge of the sanding belt could be transferred over to the EZ Lock sanding disks on a dremel. I found I can use the outer edge of the disks which will "contour" with the stone... jasoninsd You're welcome for the paper. Yes, there's a huge difference between fire agate and fire opal. Fire "agate" is actually a brown chalcedony called Sard. The name Precious Sard has been proposed for it but it never caught on. It's much harder than opal. Technically, the term "Fire Opal" refers only to bright red-to-yellow opal that has no play of color, though it's often misused to mean Precious Opal which has play of color. The name comes from its color resembling the flames of a fire. Opal of all types is much softer than fire agate and much more prone to crack and craze. I've never cut with a Dremel so I can't comment on your question about contouring. I assume the principle would be the same and the Dremel might give you more precise control.
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Post by stephan on Dec 29, 2020 10:47:47 GMT -5
I thought the fire was limonite. stephan , Close but it's actually another iron mineral, goethite. I disagree with tumbling fire agate rough. It can ruin some of the best gems if they're exposed on the surface. The iridescent layer is often just microns thick. This image shows a couple of rough stones with such sections that I gently polished as examples. They’ll make excellent cabs just by trim-sawing them and doing a bit of finish grinding/sanding. Ah! It looks like I should have been more specific. It appears that "limonite" is a very loose term, that includes goethite, but also over half a dozen other minerals.
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