Never seen anything like it. Is it a fossil?

[PoppySmile]

Found this in a customer's rock garden. They had a couple truckloads of the most random assortment of rock sizes, shapes and colors I've ever seen. I apologize that there are no clues based on it's location. All the rocks in my 'hello from Oklahoma' intro were all found in the same place. They rock itself is approx. 2¼ in. long x 1¾ in. wide x ½ in. tall. The marking isn't an indentation but the 'medium' -for lack of a better description- seems organic. If it is human-made, I'd be curious to know how. The markings are so precise as to be human-made but also seem completely natural. I've not attempted to clean it, except for a damp thumb rub or 2, but it doesn't seem like it would budge. I've shown it to probably a dozen people (none of whom were rock or fossil enthusiasts) and no one has a clue. I can't wait to see what y'all think. If I'm lucky enough for this to catch someone's eye. Please let me know if I can answer anything or post other picture etc. I can't thank you enough in advance. Have a great day. 

[FranzBernhard]

Wow!! Thanks for sharing!

I don´t know what it is. Its natural, but its also not a fossil (personal opinion, of course ).

But my mind sees something technical! Strange!

We had a discussion about fossilization of technical items some time ago, well, this is really stunning in that way. "Something technical replaced by rock". 

Please don´t take it serious, its only spinning in my mind . Your item is completely natural.

@Tidgy's Dad

[Tidgy's Dad]

I dunno. 

Limestone with a chert inclusion, perhaps? 

[val horn]

Looking at at your other pictures from your intro  several showed imprints of shells and fenestrated bryzoians, while the second collection were geologic.  This suggests your fossils are devonian or earlier.  i am guessing this was a fragment of shell something like a sea beaten piece of gastropod shell that was then storm buried and then fossilized.  The dallas paleontogy society is a fossil  club.  I would talk to them about your most interesting finds.

[Rockwood]

I have to include a caveat for a possible bias here. I collect in the glacial material from the splitting of Little Kineo mountain from Mt. Kineo, a deposit of rhyolite.

Weathered rhyolite is what I see. 

[val horn]

Hey Rockwood,  I wont put money on your being wrong.

[Rockwood]

6 minutes ago, val horn said:

Hey Rockwood, 

Well if the size of my example counts for anything.. . .  We flew by the ripped into ledge in a Piper cub the other day on the way back from a collecting trip to Lobster Lake. With the door open it was a great view.