Graded by NGC as a MS-62 so I’m happy with it. An 1869 Round Liberty Quarter struck by a private mint in California. There is a G under Liberty on the obverse and 1/4 at 12 o’clock on the reverse signifying it’s a quarter. The first two photos show the slab and the last two photos show the coin.
Those are amazing and I have two, one is in a bezel and the other isn't, some day I gotta get mine graded as the grade takes it up in price! Yours is unique as it doesn't have the Cal, so that makes it special, to me anyways!
Not sure how universally these are considered "US coins" (as opposed to private issues), but I'm not aware of any smaller US denomination of gold...?