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Everything posted by 4meter

  1. The services of a professional assayer would be the next step if the original poster would like to know if there is anything of value and how much per ton. The samples my be just pyrite with minor amounts of other metals; just enough to produce other colors in the sample beside the normal brassy color of pyrite. I have pulled samples of pyrite from the ground that looked "silver".
  2. Well, based on what we know so far, and after consulting my minerology books; I would place this sample in the arsenic sulfide group. Maybe Arsenopyrite (best fit so far), Cobalite or Skutterudite (that really is a mineral name). All of these have a metallic luster, gray-black streak, silver gray to silver white color, 4.5 to 6 Mohs hardness, not fusible, will not react with HCl, all tend to be massive in sample view. Now, if we had some nitric acid and could do a bead test, we could pin it down to one of the above.
  3. We can run out stibnite; would have fused easily at the tips of the sample. For future reference, when doing a fusion test, use a sample that is just big enough to be handled with by tweezers. Strike the sample with hammer to see if there is a garlic smell. If you have a piece of unglazed porcelain, rub the sample against it and then smear out the streak out. Take a clear photo to show us. A hardness test would be helpful. Do you know how to do a Moe's hardness test? You have tried Hydrochloric acid to dissolve it with no reaction. Do you have some sulfuric acid (battery acid)? If so, carefully, & out side, see if a small sample with dissolve in a small bit of battery acid (a few sample grains 1/2 the size of a BB & 3-4 eyedropper drops of acid) The other acid used for testing is nitric acid, but most do not have access to nitric acid. Can you tell us what county/town, in Calif the location is near? That would help narrow things down without giving away the location.
  4. If it is/has stibnite in it, easy way to tell is to take a small splinter in the flame of you r lighter. If stibnite is present, the splinter will fuse or turn into a melted ball. Stibnite has the lowest fusion temp of nearly all minerals. On the geo fusion scale, stibnite is 1. I agree with another, this looks like a massive sulfide deposit. Could also have arsenic in it. Rub against a hard metal an see if a "garlic" odor is present. If it does, it has arsenic. If you try the fusion test, see if you detect a "sulfer smell" from the sample. If you smell sulfur, its a sulfur salt.
  5. Research the "laminated brown ores (iron) of Texas. The specimen does look like an example of sedimentary iron ore formations.
  6. Hello Dilla1080, I believe you have a sedimentary rock with "molds" created by "load casts" features. From the photo # 4 it is clearly shown that there are alternating layers; some look like sandstone others shale. When the sediments were deposited as sand (sandstone) & mud (shale) a denser, thicker sand layer, which was rapidly deposited over the muds, sank into, and displaced the muds. This created the pattern seen in photo #1 & #2. Later the whole sequence was "cemented" together into a solid rock layer. Erosion has exposed the rock and we now see the "molds" or "holes" in the lower layers in which the sand sank into. The sand has been removed by erosion or broke away from this layer when the rock weathered out of the rock layer. Its a very nice rock you have there.
  7. Maybe a sapphire; could also be tourmaline or blue plagioclase feldspar. Do you know how to do a hardness test? Very nice pink/red minerals in the background. Looks like rhodochrosite. Did you find these?
  8. It's a soak um deal. 1 day & up to 1 week depending on material and how much iron staining. I.O. also gets out "Wad" staining to.
  9. The rock the mineral is found in is a metamorphic rock. Maybe a phyllite or low grade schist. I suspect the mineral shown is hornblende, but would no rule out staurolite or tourmaline.
  10. I have heard of Yooperlites before, but not of Omars. Thanks for sharing the link about these rocks Stillweaver!
  11. Its not a meteorite. From the video alone, I cannot tell what type of rock this is. Can you can supply us with some clear, close up photos? Its a very interring rock.
  12. You will never find the mineral olivine in a metamorphic rock. Olivine is only found in some basalt rocks. Since you found it in on lake Superior, I can say with certainty that the green material is the mineral serpentine. No need to find a Gemologist, this is not a gem. A very nice sample of serpentine. O! Greenstone, is an ancient basalt rock that has been metamorphized. I believe the Greenstones of Michigan are around 1.8 to 2.5 billion years old. They represent a time when the North American continent was tearing apart along its, then, western, northern and eastern parts creating what are know as "Flood Basalts". You can see similar Greenstone in Shenandoah National Park and the Blue Ridge Parkway.
  13. Like Bob said its a metamorphic rock. I believe the green vain material is the mineral serpentine.
  14. The black flaky minerals are biotite, the gray, "glassy" mineral is quartz, the yellow/brassy colored minerals that pepper the sample is pyrite and the flat yellow minerals are either muscovite or phlogopite. You are the proud owner of a schist (metamorphic rock).
  15. Is this the same sample as in first picture, just split open?
  16. Cool looking sample! Here are a few guess that might help pin it down. Massive augite, massive hornblende, anthracite coal & pitchblende (uranium ore), just to name a few common black colored minerals. The last one named, to test for uranium, put it next to your goldfish and turn off the lights. If the fish glows its pitchblende; just kidding!
  17. The white sample looks like box-work quartz, calcite or possible feldspar.
  18. Woo, lets stop right here with the Tektite idea. Tektites are glass formed by the melting of terrestrial rock during the initial stages of an impact crater formation. They are black and glassy because they are glass, similar to obsidian. None, to very minor amounts of iron are in Tektites. I'm no expert on impact craters but your "Tektite" pictures look nothing like the samples I have seen in privet and academic collections. Terrestrial astro blems, as impact sites are know, are so rare that to find anything created by such an event is highly improbable. That is unless your on the moon, then it is everywhere. The other posters are correct, the sample under discussion has a think rind of goethite or limonite. The underlying mineral must have iron in it. Looking at the shapes on the outside of the sample eliminates hematite, wrong crystal form. I still assert that it is a cluster of iron bearing almandine garnets. My baseball/Softball size almandine garnets from N GA, came out of the ground looking like the sample. Only with a lot of scrubbing and soaking in oxalic acid did they look like almandine garnets.
  19. Funny that another member posted the photos of the garnet ball, as I have garnet photos to post. I was walking a wash on the North side of Tucson today, when I came on some quartz and feldspar fragments that had been transported down from Mt Lemon. I picked up several pieces, planning to cut these into squares and turn into thin sections to use with my new polarize microscope. After cleaning the samples I had a look under my 20X/40X bino microscope. I first had a look at a plagioclase feldspar sample. To my surprise I saw all these beautiful, small, honey-orange garnets. They are the manganese rich spessartite garnets. I decided to give a go at getting photos through the microscope with my iPhone 5. The first are the garnets at 20X and the next are at 40X. Next, as I was washing the quartz sample, I was able to clean most of the dirt off except two spots. Turnes out the dirt is two large garnet fragments. These are the iron rich, almandine variety. You can see the parting (looks like cleavage but not). These photos are just the iPhone camera zoomed in on the rock and garnet. I need to find a good way to evenly illuminate the mineral for photographing, but these were a nice first start.
  20. It is a Garnet Ball; that is a lot of garnets all grown together. Many of the outside minerals show the classic dodecahedral shape. Might be the iron rich, almandine variety of garnet.
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