Rock ID?

[Kittysnax]

Ok, I have no idea where to post this, so just wanted to note that heh.

So I found this rock in my box-o-fossils. It didnt look like a fossil or any matrix I've seen. It looks to be covered in quartz or some other "sparkly" mineral. My closest guess would be granite or somthing, but Id like to see if anyone else can give an ID before I wash it and put it in the tank. The pics are crap, somthing is wrong with my camera, and closeup pics are not its specialty anymore. D:

[Kittysnax]

well i couldnt find vinegar and it couldnt scratch glass so i guess its a no go...someone on TPT suggested I try that. sad face

[cichlid1409]

looks like it might be flint

[dblondfemme]

okay..can you scratch little pieces off with your fingernail? To me it looks like a breccia inclusive (contains rough edges stones/minerals of various compositions) sedimentary rock from here that contains clumps of quartz. However it may be an igneous rock with pegmatitic texture- large crystals.

[dblondfemme]

oops you said it DIDN'T do a scratch test. If you have an old piece of mirror or glass or tile try scratching it on that in a corner. OR try scratching on another type of stone.

[myjohnson]

Don't know what it's called but there's tons of it on the beach at Freeport.

I have some of the exact same rock.

[dblondfemme]

hmmm worst case scenario... it is a type of concrete with glass in it lol. Houston itself is too young to have it's own rocks. the land has to be over 100,000 years old and Houston isn't. The further south you go from Houston.. the younger it is. So now I'm not sure. Most rocks you find... are imported *shrugs* There is silica content....I dunno. Myjohnson... does it crumble at all? Since you see it on the beach I am not leaning more toward sandstone/sedimentary rock unless it is found toward a pile of crumbled concrete.

[Kittysnax]

honestly I am not 100% sure where I found it. I think I MIGHT have found it in OK, but I have no idea. The black parts look similar to lava stone, with pits and grooves, where as the white crystally part is just that, white and crystally. It has a small cluster of what looks like "quarts fingers" in a nook, and then is powdered with it. It is also a very dusty type rock so my guess is it wouldnt be water-safe LOL.

[myjohnson]

hmmm worst case scenario... it is a type of concrete with glass in it lol. Houston itself is too young to have it's own rocks. the land has to be over 100,000 years old and Houston isn't. The further south you go from Houston.. the younger it is. So now I'm not sure. Most rocks you find... are imported *shrugs* There is silica content....I dunno. Myjohnson... does it crumble at all? Since you see it on the beach I am not leaning more toward sandstone/sedimentary rock unless it is found toward a pile of crumbled concrete.

You sure about this?

I studied a little oil and gas and from what I know there are rocks formations under Houston.

The Houston area has over 150 active faults (estimated to be 300 active faults) with an aggregate length of up to 310 miles (500 km), including the Long Point-Eureka Heights Fault System which runs through the center of the city. There have been no significant historically recorded earthquakes in Houston, but researchers do not discount the possibility of such quakes occurring in the deeper past, nor in the future.

The Long Point-Eureka Heights Fault System is a system of geologic faults in Houston. It runs beneath the metropolitan area from the southwest to the northeast. The various faults are characterized as normal faults, meaning that the downthrown side is in the direction of the dip of the fault plane. This fault system as well as others located in nearby parts of Texas are believed to have formed millions of years ago during the formation of the Gulf of Mexico.

In geology, a fault or fault line is a planar fracture in rock in which the rock on one side of the fracture has moved with respect to the rock on the other side. Large faults within the Earth's crust are the result of differential or shear motion and active fault zones are the causal locations of most earthquakes. Earthquakes are caused by energy release during rapid slippage along a fault. A fault that runs along the boundary between two tectonic plates is called a transformed fault.

[emmanuelchavez]

The fossils look like crinoids.
I'm inclined to say it's a fossiliferous limestone with possibly some sparry calcite. The pictures are a bit blurry, it took me a while to notice the crinoids.