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Post by rmf on Apr 21, 2024 14:50:48 GMT -5
Could it be the Prophecy Stone? If it weighs higher than normal. From what I found on the web "Prophecy Stone" is just a limonite psuedomrph after pyrite/marcasite. so no the above has the wrong crystal structure to be PS
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Post by rmf on Apr 20, 2024 13:05:14 GMT -5
check hardness if mohs H=2 then selenite/gypsum. My guess it is barite so it should have higher density than an equal size agate.
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Post by rmf on Apr 11, 2024 11:23:31 GMT -5
I am thinking that Brazilian Blue quartz is a quartzite with dumortierite grains in with the sand originally. I thought I had info on that but can't find it. It is not a tough as the fancy jasper shown above. Both should be a hardness of 7 though the fancy jasper is much tougher
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Post by rmf on Apr 11, 2024 2:43:28 GMT -5
jleona75 degree in Mining Engineering with Geology minor. 8th grade science got me interested in rocks and it all went down hill from there. Only worked in mining 14 yr then went to computers.
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Post by rmf on Apr 9, 2024 18:29:00 GMT -5
usually we don't have clear enough agates to see the sparking. If the agate is cool to the touch then sparking is OK since it is being abraded with the 80 grit. Use lots of water to not scorch(where it builds up heat and the heat pops the agate/quartz) the agate. You should not need ludicrous water (Space Balls ref) but having a good flow keeps the sparking down. Also quartz is also piezoelectric and just rubbing a clear quartz and some chalcedony will get you a flash of light though you may need to be in a dark room to see it. So if you fall under scorched but still sparking then you are ok
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Post by rmf on Apr 9, 2024 18:20:43 GMT -5
Hanzo0515 it does kind of look like wood to me but given where you found it maybe not so much. Since MN has been glaciated it is possible to get wood from glacial till, though usually small pcs. But your best bet is Iron rich rhyolite. Do you have access to a rock saw? Hardness you listed above would be 5 or greater. Try to scratch with agate/quartz. if it scratches then h is less than 7. That would be a good range for rhyolite
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Post by rmf on Apr 9, 2024 18:07:46 GMT -5
Some times life is such a grind. Rough ground 52 preforms on the 30 grit sintered wheel today. Hands are tired, but life is good!!!
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Post by rmf on Mar 31, 2024 7:12:51 GMT -5
vegasjames do you have names that go with the rhyolite images? Also, I did not know Goldfield Jasper ( #2 & #10 above) was a rhyolite. Thanks for the post. I am not a big rhyolites fan in general because many do not polish well but Goldfield Jasper is one of my favorites.
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Post by rmf on Mar 30, 2024 15:52:54 GMT -5
rockbrain is that GA Lace Agate (aka Summerville Agate) or Mexican Lace?
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Post by rmf on Mar 30, 2024 15:50:10 GMT -5
Rockwood and Harriman both had Iron and coal close by.
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Post by rmf on Mar 30, 2024 9:48:09 GMT -5
rolleyholeman1 Without giving out any "best fishing hole" kind of secrets. where? Herriman area has had Iron smelting in the past and there are coke ovens at Dayton. Also, many places have burned coal. The white blebs look like limestone so I am guessing Iron furnace slag.
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Post by rmf on Mar 30, 2024 9:40:57 GMT -5
If the rocks are well rounded to start, then use 220 grit to start with. No need to use coarse. Then proceed to finer grits as normal and polish.
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Post by rmf on Mar 30, 2024 9:39:13 GMT -5
I have never dressed a Nova wheel. Never hat the need. Plated Galaxy wheels, and turbine wheel all slow down after the first 200 stones. I have used 80 grit turbine, 80 grit smooth Galaxy, 80 grit Hex galaxy never needed dressing. All slow down after the first 200 stones. It is a fact of plated. I have recently started using sintered wheels 30 grit coarse (equal to a new plated 60 grit) after 1000 stones no noticeable difference between now and out of the box. 60 grit sintered same but lower grind count
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Post by rmf on Mar 27, 2024 18:03:47 GMT -5
Diamond wheels are great until they are not. When I polish (Agates and Jaspers and obsidian) I take them down to 3000 grit via diamond Nova wheels. I have and 8000 and a 14000 diamond but Then it becomes about speed of finishing. So I go to conventional polish. I have used Tin Oxide(SnO) for 50 years and have not had good results with cerium. However, some on here use a much higher grade of cerium than I have tried. That said the SnO I add about 3oz of Linde A with the tin to speed my work. I use to polish on leather with a spray bottle. When the end plate leather failed they nolonger carried the good glue so I just used my muslin wheels. I polish almost everything on Muslin with SnO+ linde A and get a great polish. The key whether Leather or muslin is to start wet with the polish and work to dry. Especially quartz, glass, and opals are heat sensitive so I use a mister to keep the heat down as well and use the fine fibers on the edge to lightly polish the heat sensitive part after I have worked the wet on more of the center of the buffer.
Other rocks that are softer like travertine I go to 8000 Nova wheel. I discovered that Lapis polishes best on a diamond cloth belt, not a resin wheel.
Polishing happens in two steps wet does some cutting and dry finishes the polish but the work you do while it is wet is key.
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Post by rmf on Mar 24, 2024 13:27:53 GMT -5
Possible stones: it is semi translucent so it it could be calcite, fluorite, talc/soapstone, alabaster though it is usually more orange to white. If it is talc or soapstone the mohs hardness should be 1 for talc and maybe a little harder for soapstone but both should be less than 2. that means if you can find a place that does not show much then you should be able to scratch it with your fingernail. Your fingernail has a mohs hardness of about 2.5. If it is calcite which has a hardness of 3 you should be able to scratch it with a copper penny that is pre 1982. If the copper penny leaves a copper streak on the carving it is fluorite which has a mohs hardness of 4. That should be sufficient diagnostics to determine the mineral. Also, talc and soapstone should feel slick on you fingers like soap after rubbing with your fingers. That is why it is called soapstone. Let us know what you learn. enquiring minds want to know
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Post by rmf on Mar 18, 2024 19:57:49 GMT -5
rolleyholeman1 looked at you images. #1, 2, and 4 are not what I would call TN Agate (a.k.a Paintrock Agate) They have agate and quartz but do not match the typical material. Image #3 is calfkiller agate. the top stone on image 5 is a chert with fossil bits the dark color from organic carbon. The lower two I would put in the chert category but may also be calfkiller agate.
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Post by rmf on Mar 11, 2024 19:30:29 GMT -5
BTW the Highland Park Templates come in plastic and there is another set available in stainless steel. The stainless set has 10 templates and the plastic has 8 templates
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Post by rmf on Mar 11, 2024 19:24:25 GMT -5
If you have the drums the 3x1.5# is the same frame that they use for the 33B which takes two 3A drums.
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Post by rmf on Mar 6, 2024 13:16:17 GMT -5
oolitic agate from WY
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Post by rmf on Mar 5, 2024 16:51:08 GMT -5
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