Help Identifying Mineral/Rock?

[Invicta]

Help Identifying Mineral/Rock? -- Solved

I live in West Central Texas and when I take my dogs walking, every now and then I will find and pick up an interesting-looking rock or random nodule, because I like collecting interesting stones. I found this one earlier this morning (it has not been polished/tumbled, it looked like this when I pulled it out of the snow and mud.) Most of the time, they've been easy for me to identify, but I'm confused by this one. The cleave makes me think of some kind of obsidian, but at the same time, the colors almost make me wonder if it could be some sort of jasper or agate? It's a weird greyish-green, brown and white. Smooth and I would call it waxy, with small fibrous strands in the broken/cleaved white area. Is anyone able to make a rough guess about what it could possibly be?

 

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[CRUSADER]

White ish one looks like flint to me.

 

[blauer]

If this was posted in the geological forum I would say it is.....

 

[tamrock]

Looks like a rock mostly comprised of silica. Possibly a piece of what's left of the mountain range known as the ancestral rocky mountains that once existed 300 million years ago. introduction

 

[TheCannonballGuy]

Your nodule is definitely chert.
Chert: Sedimentary Rock - Pictures, Definition, Formation (geology.com)

Flint is one of the many varieties of chert. Flint is usually black or very-dark gray, as seen in a photo of a broken-open white-exterior flint nodule here.
Chert - Wikipedia

However, some flint is light-grey to white-ish... so Crusader's ID is correct. See the photos here:
flint - Bing

You said:
> The cleave makes me think of some kind of obsidian [...]

The cleave you are seeing is called Conchoidal Fracture... which is mentioned as a characteristic of chert (and flint) in the description at the link above.

You also said:
> it has not been polished/tumbled, it looked like this when I pulled it out of the snow and mud.

After your chert/flint nodule got eroded out of the Limestone matrix it was formed in, it got tumbled for centuries in a (now vanished) fast-flowing river. Then the potato-shaped nodule somehow got broken into the sharp-edged shape you found.

 

[xaos]

Yep...def Chert