weird rock formation from a field

[DENNIS MIN]

All,

I got some field-picked rocks locally and after unloading I found a rather ordinary rock with an internal formation. Inside a small hole about an inch across, I saw 2 geometrically shaped "crystals".

Each has a nicely shaped pyramid look to it. It's kinda soft, because scratching the dirt out caused some scuffs.

What is it? Looks like a limestone type variety, but the crystal shapes has me guessing.

D>
<image src="http://forums.yesterdaystractors.com/photos/mvphoto5566.jpg"/>

 

[K Effective]

UFO flight recorder?

 

[K Effective]

Very cool, whatever it is!

 

[db4600]

Petrified Viking coin purse.

 

[neverfear]

I agree, looks like a crystal structure formed it. Nice conversation piece for the den,man cave,shop or whatever you prefer.

 

[Buster]

Probably worth millions of dollars if someone else owns it!

 

[Eldon (WA)]

Thunder egg!

 

[kcm.MN]

Where part of which state was this found?

 

[DENNIS MIN]

kcmMN,

Well, seeing as I didn't pick the rock my self, I'd say the area was south of Minneapolis and north of Rochester. That's the best I can do for a locate.

Do you have an idea what this rock is? Where does a fellow go to find out anything about it

D.

 

[SweetFeet]

Geodes can have other formations inside... but they are usually a rounder rock and typically have crystals inside of them.

Thought teen daughter had a book about Minnesota rocks - but can't find it and she's gone at work.

 

[DENNIS MIN]

Buster,

It is yours for half that price! You buy it from me and make 50% profit? LOL.

I still would like to know what it is. I am sure it is not gold, silver, frankincense, or anything of significant value.

D.

 

[farmerwithmutt]

Quartz i have a lot in my area . If i remember it's formed by the pressure of the earth. I have 3 places on my farm all at the same elevation and on North slopes . the rest of the flint is different in other areas i should know lots of up close and personal time picking rock. Even more oddly they have a different sound when banged together

 

[DENNIS MIN]

Farmerwithmutt,

I am unsure of anything about rocks, other than they get tiresome and heavy. I thought quartz was a harder rock, I accidentally scratched these with a small screwdriver digging out the dirt. Seemed soft to me.

Still am guessing, so you still have one up on me. Glad I didn't have to pick all the rocks to find this one though.

D>

 

[SweetFeet]

I think Quartz is also translucent... and your's seem opaque.

 

[CBBC]

If the main mass is lonestone, the pyramid softer formation could be an inculsion of some other sedimentary rock.
If the limestone were to be subjected to heat and pressure it would become metamorphic and become marble.
Crystals etc can be formed within... however they are generally very hard. If you say they are soft then likely just a chunk of sedimentary rock- sandstone, or slate etc.
How the pyramids formed??? I have no idea.
Grant.

 

[showcrop]

The general structure is related to a Geode, but a true geode is nearly round and hollow, with crystals inside. The surrounding rock does look like limestone, so it appears that the crystal grew out of the limestone, which would make them calcite. Calcite, like quartz and many other minerals, comes in many different colors depending on the impurities contained in the limestone that it grows out of. I have some very bright orange calcite that my father got out of a ledge cut of an interstate highway construction project.

 

[Janicholson]

My input is: Staurolite crystals. Google it, I have a cross shaped one, Jim

 

[Traditional Farmer]

Pyramids built by the miniature people that used to live in your area until the Possums and Coons wiped them out.

 

[kcm.MN]

(quoted from post at 17:39:11 11/02/17) kcmMN,

Well, seeing as I didn't pick the rock my self, I'd say the area was south of Minneapolis and north of Rochester. That's the best I can do for a locate.

Do you have an idea what this rock is? Where does a fellow go to find out anything about it

D.

Thanks Dennis. No, I don't have a clue, but I've got some friends who are geological wizards. If you don't mind me sharing the pic, I'll ask around.

One thing I notice that really puzzles the heck out of me is how the three points all seem to come towards the same point; all in alignment. I've never seen anything like it. Hopefully I'll have an answer for you by tomorrow.

Keep your fingers crossed! :wink:

 

[funky_g00]

My wife took a look (she grew up rock hounding in MN) and thinks sodium crystals - especially if they are easily scratch-able. Staurolite would have the cross-grain and is much harder, calcite is rhombus shaped not so much pyramid. She says it looks like it has lots of impurities, but has to be something with the right molecular structure to form that way.
<image src="http://forums.yesterdaystractors.com/photos/mvphoto5574.jpg"/>
HTH, but she thinks it looks cool!

 

[X-Y switch]

Probably calcite in a geode.

 

[bmack95hd]

Could be a vortex gps that some hippy from Sedona, AZ. lost. Just my SWAG.

 

[Olliejunkie]

Looks kinda shaped like a fence post.