I found this near shoreline of Upper Michigan lake, near Wisconsin border. I screwed up and cleaned it a bit. There was a bit of what seemed to be a pine tar like substance on one side. I know it's copper, just can't tell if its worked/formed, or perhaps natural state left by the glaciers coming down from the Kewenaw Peninsula.
![image.jpg image.jpg](https://www.treasurenet.com/data/attachments/810/810959-16c689bd137eeb45d11c4df7917f4b41.jpg)
![image.jpg image.jpg](https://www.treasurenet.com/data/attachments/810/810959-16c689bd137eeb45d11c4df7917f4b41.jpg)