Tice's button book listed as NA206A8, Albert's button book as NA102. Civil War Navy coat button.
Missing half- has the eagle perched on the anchor below her talons on the front. The edge of the button has nice clear stars. It has the lined background to make the detail stand out better. TAs you can see it has the original gold gilding in just the right places to make the detail stand out.
The original back and shank are intact with the generic RMDC backmark of "EXTRA QUALITY". This was used so the button's retailer could sell the button without advertising for the actual button maker.
Source: https://shilohrelics.com/cgi-bin/display_Item.asp?120232