Mysterious Montana fossil

[FossilizedJello]

Recently, I took a class that required me to go to Montana to study Geology. One of my finds included this fossilized object that I would consider some type of seed or pine cone of sort. Any help is greatly appreciated.

[JohnBrewer]

@Plantguy

[DPS Ammonite]

What rock formation and age rocks did this come from? Where did you find it?

 

It looks more a mineral nodule with a needle like core with tabular crystals on the surface. If it is unusually heavy it might be barite. See photo from Mindat: https://www.mindat.org/photo-967006.html

[Mark Kmiecik]

I agree that it appears to be geological in origin. A very cool specimen nonetheless. 

[Plantguy]

I like it also! Geology in Montana sounds mighty cool. Yep having additional info may narrow/pinpoint the ID...thinking mineralogic as well. Did you all cover mineral properties in class? streak, hardness, etc?

Looks like the western part of the state has some occurences of barite if that is what it is....

from here: 

http://www.mbmg.mtech.edu/sp28/mina-l.htm

MINERAL AND WATER RESOURCES
OF MONTANA

Montana Bureau of Mines and Geology
Special Publication No. 28
May, 1963

 

Regards, Chris 

[hemipristis]

It's a marcasite nodule (chemically the same FeS₂ as pyrite, but a different chemical structure) that has formed around some lignite (pre-coal).  It's a common association.  In some Cretaceous strata in NJ and NC, it's not uncommon to find small pieces of amber mixed in

 

 

ETA:  

Note that marcasite is very unstable once exposed to air.  The FeS₂ reacts with moisture and oxygen in the air and can rapidly rust and disintegrate. This is called "pyrite disease'. If you wish to keep this specimen and you live in a moist climate (like NJ), keep it in an airtight container along with a desiccant (I use silica gel crystals in cheesecloth. Silica gel can be found in any craft store, as it is used to dry flowers).