Treasure Found

Found what I believe is a treasure if you are in the dime crazy like my mother. I couldn't find the owner that left it outside my car door. 

I took it to a want to be a coin collector. The band around its edges and loop are 14kt the ½ cob is sterling silver. That was all he could say.

I have many hours of research pre-1700. Could someone please help me identify and tell the origin of it?

 Pictures roughly cropped and rotated … 

 Then, using those cropped pictures, this was a search result: 

N#61952 

 Bolivia / Philip IV (1621-1665) / 1654-1666 

Thank you by chance by looking at it estimated value and grade

Context is important here. I have  these type of cob coins from Petosi Bolivia of various denominations and other Spanish colonial countries but most of these are unfortunately not very valuable. They are crude by their very  nature because details were not of primary importance to Spain where they were intended to go. Silver content, purity, weight, and shear volume was the primary concern to the King. There are an abundance of attainable and affordable crude cob coins available in relative poor condition such as your example. Find one with all the information intended for the coin such as date, assayer, ruler, etc. and which actually survived circulation for hundreds of years and you have a valuable specimen. The more details, the more valuable.  I would value this specimen at around the $15 - $20 range. Because of this, many people decide to take low value cob coins like this and make interesting jewelry out of them. Together, they are beautiful and interesting.

Edit. In addition, if the cob coin can be attributed to a specific shipwreck such as the Atocha, that too would add value regardless of condition.

https://www.cedarchestsanibel.com/spanish-treasure-coin-half-reale.html