Amethyst Vow

A tusk ornament  made out of an Amethyst Dragon scale. 

This can be used as a focus for your cleric spells. While attuned to this item, you can cast the message cantrip. 

In addition, this item has 5 charges and regains 1d4 + 1 charges after a long rest. You can expend a charge to give yourself advantage on an attack roll, ability check, or saving throw. 

When you use the last of the items available charges, roll a d20. On a 1, the item loses the ability to regain charges.