This stone has embedded white strains of what appears to be plant material.

[Rocsteddie]

Found this stone in Northern Mn. just laying on top of the ground.
Near old mine dumps .
It is magnetic mostly with a few small areas that are not.
I have no idea how or why these white rectangular objects ended up attached to this stone.
Scrub stone with soap and water really hard with no change.
Thanks for interest and any info View attachment 1247783 View attachment 1247784 View attachment 1247785 View attachment 1247786

 

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[Eu_citzen]

Gabbro.

 

[Rocsteddie]

View attachment 1249301 View attachment 1249299 View attachment 1249300

Gabbro.

Here are some pictures of stone close up. Note how white material over lap each other. IMO not part of stone at all. Stone it's self may be Gabbro. Open for suggestions as to what they may be. To me they appear to be some sort of a flower peddle. Just saying. Thanks for info.

 

[Eu_citzen]

The white material is called plagioclase. Due to weathering (being exposed to rain, wind etc) it really shows a strong contrast between the white plagioclase and the blackish pyroxene.
When these two minerals occur together in a rock and shows "big" grains, we call it gabbro.

That the plagioclase seemingly overlap has to do with the crystallization process, they had a lot of time to grow big.

 

[Dakota Sioux]

That white material is crystals of plagioclase feldspar and are not just on top. Eu has got it

 

[Rocsteddie]

That white material is crystals of plagioclase feldspar and are not just on top. Eu has got it
View attachment 1249318

Thanks so much for the info. So if I have the stone cut in half which I will ( I know someone with a Water jet cutting machine) that the inside will have these crystals inside the stone? That would be awesome to see. I've reconsidered and decided not to cut rock. Yet.

 

[Dakota Sioux]

Yep nice rock roc

 

[IAMZIM]

That white material is crystals of plagioclase feldspar and are not just on top. Eu has got it
View attachment 1249318

There is an entire mountain made up of this stuff here in Montana. And when I say an entire "mountain", I mean it is part of the ROCKY MOUNTAINS. So not just a little hill. I walked five miles up to a really neat lake near Elkhorn Montana, and that rock was on the trail almost the entire way.

 

[Rocsteddie]

There is an entire mountain made up of this stuff here in Montana. And when I say an entire "mountain", I mean it is part of the ROCKY MOUNTAINS. So not just a little hill. I walked five miles up to a really neat lake near Elkhorn Montana, and that rock was on the trail almost the entire way.

IAMZIM thanks for info but is it found in areas of Minnesota like that in Montana? Also is Gabbro magnetic?

 

[IAMZIM]

IAMZIM thanks for info but is it found in areas of Minnesota like that in Montana? Also is Gabbro magnetic?

No clue, never took a magnet with me when I was there, and the thought to use one never occured to me. But, if it is associated with feldspar, then I can believe that it could have enough iron in it to be magnetic. Here, wherever you find feldspar, of any variety, Microcline, Orthoclase, we even have Albite, you will find iron in some form or another associated with it, so I can believe that it might be magnetic. The mountain that I have seen the Gabbro is part of the Boulder Batholith, a huge area of granite. As far as Minnesota goes, and areas found, the only place I have been in Minnesota was Hoka, next to the Mississippi river, which was all sandstone. I only lived there for 6 months. So that is all the experience I have there, sorry. If there wasn't about 10-20 feet of snow there, I would go grab one of those rocks and take a pic of it for you, because it looks almost exactly like what you have.

 

[Rocsteddie]

No clue, never took a magnet with me when I was there, and the thought to use one never occured to me. But, if it is associated with feldspar, then I can believe that it could have enough iron in it to be magnetic. Here, wherever you find feldspar, of any variety, Microcline, Orthoclase, we even have Albite, you will find iron in some form or another associated with it, so I can believe that it might be magnetic. The mountain that I have seen the Gabbro is part of the Boulder Batholith, a huge area of granite. As far as Minnesota goes, and areas found, the only place I have been in Minnesota was Hoka, next to the Mississippi river, which was all sandstone. I only lived there for 6 months. So that is all the experience I have there, sorry. If there wasn't about 10-20 feet of snow there, I would go grab one of those rocks and take a pic of it for you, because it looks almost exactly like what you have.

Thanks for the very helpful info and education. As far as feldspar(will need to research that) goes that makes since because we have a lot of iron here on The Iron Range.
Also the shape and color variations of this particular stone has me wondering if maybe there was some sort of ( call me crazy. a lot of people have.) human influence on the shape and color. Is that possible IDK.

 

[EricTheCat]

I have found gabbros around here and also up in Northern Minnesota. I never thought to take a magnet to one though. They can be pretty. I think I gave the last one I found to my mom so she could put it around her garden.

 

[Eu_citzen]

Gabbro often is accompanied by magnetite, making it magnetic. Has nothing to do with the feldspar.

 

[IAMZIM]

Gabbro often is accompanied by magnetite, making it magnetic. Has nothing to do with the feldspar.

Didn't mean to make it sound like being magnetic had to do with the feldspar, just have observed here that there is alot of magnetite, pyrite, and raw iron with the feldspar here. You are absolutely right!

 

[Eu_citzen]

Didn't mean to make it sound like being magnetic had to do with the feldspar, just have observed here that there is alot of magnetite, pyrite, and raw iron with the feldspar here. You are absolutely right!

Good observation. If it is plagioclase feldspar, the rock is often magnetic because it more often contains magnetite and/or pyrrhotite.
Usually also more to the mafic composition (quartz-poor) mineral wise.

Pinkish or reddish feldspars, which are often K feldspar do not all that often come with as much magnetite. Hence none magnetic rocks, or rather weakly magnetic.

 

[ice9]

It's an interesting cutting material, if you want to get into lapidary. Look up "Chinese writing stone", "flowerstone", or "daisy stone".

Sawing it in half will expose more of the lath-like feldspar crystals. In flowerstone, they're bunched up and actually look like little flowers, amazing stuff.

Found a 25 lb piece near Hope, BC, this Xmas.

 

[Rocsteddie]

Another unanswered question of mine.

View attachment 1262386 View attachment 1262385 View attachment 1262386 View attachment 1262387

The white material is called plagioclase. Due to weathering (being exposed to rain, wind etc) it really shows a strong contrast between the white plagioclase and the blackish pyroxene.
When these two minerals occur together in a rock and shows "big" grains, we call it gabbro.

That the plagioclase seemingly overlap has to do with the crystallization process, they had a lot of time to grow big.

Just another observation that I noticed was how some of the plagioclase appear to be compressed in locations that are darker in color and quite different from the more uniformed shaped ones. Don't crystals solidify. Here are a couple of pictures to show what I mean. Note lower right of first pic. How is this possible? Had to have happened before the material became solid. IMO

 

[Eu_citzen]

View attachment 1262386 View attachment 1262385 View attachment 1262386 View attachment 1262387

Just another observation that I noticed was how some of the plagioclase appear to be compressed in locations that are darker in color and quite different from the more uniformed shaped ones. Don't crystals solidify. Here are a couple of pictures to show what I mean. Note lower right of first pic. How is this possible? Had to have happened before the material became solid. IMO

Crystals crystallize. And its kinda like riding the bus: The earlier you get on, the more room you have to sit on! (few passengers)
As the bus ride goes on people increasingly have to "squeeze" them selves in to have a place to sit.

That's why some may look "compressed", since they squeezed themselves in between other crystals late in the crystallization process.