Sciencemadness Discussion Board

How could this have been made?

HydroCarbon - 5-10-2010 at 15:28

So basically my friend found this piece of white quartz out in the woods and it has two very similar square shaped holes on both sides with a thin sliver of quartz between them. It's puzzled us for a while now as to how it could have formed. I snapped some pics a while ago, tell me what you think?

Our best guesses are:
1: It was carefully carved out by somebody.
2: Crystals formed in the holes then escaped somehow (not likely since it's on both sides).
3: Extraterrestrials made it :P



IMG_7729.JPG - 35kB One side IMG_7732.JPG - 32kB Other side IMG_7721.JPG - 27kB

The WiZard is In - 5-10-2010 at 15:50

Quote: Originally posted by HydroCarbon  
So basically my friend found this piece of white quartz out in the woods and it has two very similar square shaped holes on both sides with a thin sliver of quartz between them. It's puzzled us for a while now as to how it could have formed. I snapped some pics a while ago, tell me what you think?

Our best guesses are:
1: It was carefully carved out by somebody.
2: Crystals formed in the holes then escaped somehow (not likely since it's on both sides).
3: Extraterrestrials made it



------
Iron pyrite forms cubic crystals, perhaps it fell out. And byda
me thinks the matrix is quartzite.

[I know galena among other minerals have square xts —
iron pyrite is the most common one.]



Trivia - In the 1940 Flash Gordon Conquers the Universe
staring Buster Crab, what was Dale Arden's profession?

Xenoid - 5-10-2010 at 16:32

Quote: Originally posted by The WiZard is In  

...... me thinks the matrix is quartzite.



....No, it's just vein quartz. Quartzite is a rock, made from metamorphosed quartz-rich sandstone.

Yes, that is a hole left by a pre-existing crystal. It is important to remember that vein quartz like this is deposited from high temperature hydrothermal water solutions into a rock cavity. The rock cavity may have been lined by some other type of mineral, eg. pyrite, galena, tourmaline etc. even pre-existing quartz crystals.

When the vein is exposed by erosion, the pre-existing crystal (especially if it is pyrite) may be preferentially decomposed before the quartz (which is very resistant) leaving the hole or cavity.

Sometimes these cavities are filled with another mineral - forming a pseudomorph, the mineral takes on the apparent crystalline shape of the first mineral. Iron oxide pseudomorphs after pyrite or halite are quite common.

Nice find .... put it on your shelf!

HydroCarbon - 5-10-2010 at 18:09

Yeah we thought of that as I said, but how do you account for the fact that there's similar holes on either side with quartz in the center.

[Edited on 6-10-2010 by HydroCarbon]

Xenoid - 5-10-2010 at 18:37

Quote: Originally posted by HydroCarbon  
...but how do you account for the fact that there's similar holes on either side with quartz in the center.

[Edited on 6-10-2010 by HydroCarbon]


Uhmmm... The original (long, thin) crystal cracked at the time the hydrothermal quartz was forming! Possibly due to thermal stress. One part moved slightly apart from the other, allowing a film or thin layer of quartz to form between them!

IrC - 5-10-2010 at 18:49

This quartz came from a vein of gold. Telluride gold in fact. Possibly washed down from some operation in the hills back a hundred years ago. Did not read this thread very carefully but I am guessing it was found in a flash flood area, the location you often find such items carried a long way in under a hundred years. Looks like pyrite is correct (galena does not break along crystal grains into square shapes, I know I hammered a 5 lb piece a while ago to see).

Either a cleat, spike or old square nail was hammered into it, or blown into it by explosive shock if the hole is man made. Or more likely two pyrite crystals indeed fell out. They are perfectly square as I am holding one now. Of course the alien factor could be at work.

Since gold bearing quartz with the color in that picture usually has Te impurities as well as being intimately associated with pyrites I imagine aliens can be discounted. You can see the rust colors quartz associated with pyrites always has in that picture. I will however from now on be breaking apart my specimens looking for an embedded MP4 player. You never know?

Rogeryermaw - 5-10-2010 at 20:03

that's a puzzler! in the ozark region quartz rock is very common to find laying everywhere. my yard's so damn full of quartz i can barely dig 4 inches deep in places and i have seen some really cool fossilized pieces but that is a pretty unusual characteristic you have found. my bet is on man made. the cut just looks to perfect to have sat for any period of time with no erosion. maybe some prankster left it to be found all the while thinking "wow this is gonna screw with somebody's mind hard!"

looks like it worked!

Ozone - 5-10-2010 at 20:13

Pyrite in quartz is very common in the Black Hills (and most everywhere there is mature pegmatite). So is tourmalene in quartz (particularly schorl in hornblende or mica schist), but then the hole would be hexagonal.

Cheers,

O3

[Edited on 6-10-2010 by Ozone]

Xenoid - 5-10-2010 at 20:32

Quote: Originally posted by Rogeryermaw  
... my bet is on man made. the cut just looks to perfect to have sat for any period of time with no erosion. maybe some prankster left it to be found ...


...... Crap!

IrC - 6-10-2010 at 06:06

Arkansas quartz is mostly Quartzite. No gold there, or pyrite as far as I know. Diamonds however are very common.