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I don’t know much about were I live, I am from ny and only moved here a few years ago. I found it in Smithfield nc we’re I love with my dad and kids now.. I wish I had more information. Yes the rock was wet pic and dry If I had a rock tumbler I would love to see what it would look like clean and polished. But when I wet sand paper 120 grit to try and shape it it just ate it and did nothing really to it. If u would like it u can have it. I just really would like to know what it is. If u want I can take new pics. But yeah it had no reaction to a butter knife scratched the glass and scratched porcelain and didn’t leave and streak color that I could see. It knowing is driving me nuts lol. enter image description hereenter image description hereenter image description hereenter image description hereenter image description hereenter image description hereenter image description here

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  • $\begingroup$ Pretty sure it is a type of granite, with quartz, feldspar dominating the mix. Other than the red color looks pretty much like your granite countertop $\endgroup$ – Friddy May 30 at 21:01
  • $\begingroup$ Thanks its a toss rock not to throw it back $\endgroup$ – Samantha Anderson May 30 at 21:52
  • $\begingroup$ Not sure if the transparent crystals are carbonate or quartz. I'd tell you to do the acid test, but I suppose you wouldn't have diluted HCL there with you... But I believe that reddish paint is not feldspar but actually an iron coating. And unless that's an alkali granite, I find odd the absolute lack of biotite. $\endgroup$ – Matheus May 30 at 22:11
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I'd say that's either a pegmatitic vein or a strange conglomerate.

A pegmatitic vein is basically a fracture on which a hot fluid (generally water) percolated which had a lot of ions that precipitated. Since the crystals are rather large, I think it's pegmatitic (that is basically a descriptive term of the "texture" used for when the crystals are anomalously big). It probably has quartz, carbonate, or both, albeit both would be rather odd.

An conglomerate is a sedimentary rock composed of many grains larger than 2mm.

I'm betting my buttons the red is actually iron coating - some sedimentary rocks around here have similarly colored quartz, and it's all iron coating. (oxidized iron becomes reddish and they're bloody common)

These guesses are of common things. Maybe it's something rarer, who knows.

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  • $\begingroup$ I did hit it with a hammer a few times to brake it open I did put it I. Critic acid no reaction and in vinegar and same no bubbling or anything $\endgroup$ – Samantha Anderson May 30 at 23:10
  • $\begingroup$ It has to be HCL, but it's not an usual acid and I wouldn't recommend trying to use it if you're not used to it. I just mentioned because who knows if you had it. $\endgroup$ – Matheus May 30 at 23:13
  • $\begingroup$ If u would like it u can have it, just let me know I’ll be more them happy to give it to you $\endgroup$ – Samantha Anderson May 30 at 23:14
  • $\begingroup$ Thank you for the offer, but I'm not quite the rock collector type. $\endgroup$ – Matheus May 30 at 23:17
  • $\begingroup$ No prb lol if anyone would like it let me know u can have it 🙃 $\endgroup$ – Samantha Anderson May 30 at 23:22
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I am comfortable calling your rock an Alkali Feldspar Granite. The two main minerals will be Potassium Feldspar, the reddish coloured crystals, and Quartz, the clear mineral on the broken section and the white on the weathered surface. See the QAPF diagram from Wikipedia here. Most or all of the feldspar is of the Alkaline type and amounts to approximately 60% of the rock, the remaining quartz approximately 40%. A quick search on Alkali Feldspar Granite will turn up images of rocks similar to yours.

The crystals in the rock are of typical size for many plutonic rocks, i.e. rocks from slowly cooled magma.

There is also likely some iron staining coming in from the surface.

I suspect that you will not have any acid reaction with HCL or if you did it would be from the exposed surface only. Muriatic Acid is a readily available type of hydrochloric acid you can purchase from a hardware store, used to clean cement finishes, it is stronger than dilute form of HCL used to test for carbonates, but it would rule calcite and other carbonates out. I don't expect carbonates because they are typically softer than either quartz or feldspar and wouldn't weather smoothly like your stone appears to have weathered.

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  • $\begingroup$ So I broke it open more and let it soak over night in bar keepers friend and hot water then it rained so I left it over night mixed with rain water and to find out it opal it has the glisining shifting speckles and it’s red, Orange and clear mix with it threw out the whole freaking thing now I am kicking my self in the ass 😑 $\endgroup$ – Samantha Anderson Jun 1 at 12:58
  • $\begingroup$ Sorry to hear you throw out your stone. I still believe it is a granite though. A rock with the crystal structure shown would typically not have opal in it. Opal is a hydrated (water added) silicate and forms as an alteration of existing rocks and minerals. On the other hand, other associated feldspars can have iridescence and shine similar to an opal. Labradorite and Oregon sunstone are two feldspars that iridesce see geology.com/gemstones/labradorite. Additionally all rocks look better when wet. $\endgroup$ – Friddy Jun 3 at 17:50
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This is a quartz vein that has moderate hematite alteration. There is no feldspar in this sample.

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