This is a very narrow walnut/holly banding cut at 30 degrees. It is actually just under 1/8" wide (a couple thousandths under 1/8" wide).
This enables it to fit easily, but snugly in a 1/8" wide routed channel.
A lot of this banding was used in small boxes and drawer fronts in some Federal style creations.
Inlayed and finished. The US quarter is there for size reference.