
I have posted this image of a Massachusetts shilling and my mystery item as a comparison. They are NOT to scale.
Please note that a Massachusetts sixpence (not shown here) is the same diameter as my mystery item.
Official records and legislation pertaining to the Colony of Massachusetts Bay clearly disclose the rife manufacture and use of brass and tin penny tokens that were eventually rigorously outlawed. References cite that to date no examples survive or are known. Penalties for being in possession of them include a threefold face value fine with a reward being paid to whoever potted the possessor.
It is evident there was an intent to officially replace them.