Moving Dirt, Finding History

There hasn't been much action at 765 as far as house projects go as of late. Any extra minute seems to be spent doing something for the wedding.This isn't much exception. A friend of ours that has a landscaping business happened to have a job on our street that included a dingo, a machine that turns ripping out grass from a day-long job to just a few minutes. Major score.

In place of grass? Flowers for the wedding. At least that's the plan, but for now we're waiting for a few days of no rain to lighten the load of the dirt.

{Cosmo wanted to help}

In the midst of tilling up the dirt and adding some good soil 'eagle eyes' spotted yet another historic treasure in the mound, but what it was exactly we were all stumped. After a bit of google research we found out not only what it, but also how old it really is. Before I post what the gem is I'm interested to see everybody else's guess is... (But please not cheating, googling or phoning-a-friend!)

{mystery object}