Small eagle button found. What type of button is this? Military?

[Digger92]

Been very cold here in Colorado so haven't been out detecting much. Today however it was nice enough to get an hour out in the old mining camp. I found this button lying on the surface and it was very dirty. After running it under a bit of water this was what it revealed. Never seeing buttons like this I was curious if anyone could give me some insight on it. It's 15mm around and has a screw style back. Thank you for checking it out!

 

[nhbenz]

Off of the side of a US Army cap. Holds the chin strap on.

 

[Digger92]

Off of the side of a US Army cap. Holds the chin strap on.

Thank you! That's really cool to know. Is there any way to date these?

 

[parsonwalker]

I think I've read that they are post early 20th century. Somebody will know . . .

 

[pepperj]

It's a saw nut

 

[duggap]

It's called the "great seal". First used in 1902 and still in use today.