The Singing Stones of Hamlin are a naturally occurring crystal, which hums with a barely audible song. When that tune is hummed, it has potent healing magic.
It has 12 charges that return at each dawn. For a free action, you can hum its resonance and get the equivalent of a healing word, first level for you or a party member or ally, using 1 charge.For 2 charges and a bonus action, you get a 2d8
For 3 charges and an action, you can get a 6d8
After battle, you can do a ritual with multiple stones that will cost 4 charges for every stone involved, 3 minimum. That will give you each 7d8+14 healing.
For 7 charges for at least 3 stones, you can cast Revivify.