Replica, and if so what was it a representation of?

[Digger54]

I remember handling this item that my father had when I was a child in the early 60s. Found it again when I went through my father's estate. Do not know how he got it, but know he scuba dived in the Bahamas in the late 50s. I assumed it was a fantasy replica souvenir piece because it weighs 16 grams and has what looks like a seam near the top. Curious as to what date range it was supposed to represent?

 

[Mackaydon]

Looks like a well worn (and/or 'shaved') 8-reales cob coin from the Mexico City mint.
If the assayer's initial is "J", it's Jose Eustaquino de Leon --the assayer for most of the Mexican silver coins salvaged from the 1715 fleet.
Don in SoCa