the_debt_of_time

"Violetta Black's opal ring," Mia confirmed and then looked to Harry. "This is the
one I told you your father tried to steal and send to Lily. But when he proposed, he gave
her the Potter family ring."
"I wanted you to have a Black heirloom, but nothing that belonged to Walburga,"
Sirius said.
"For which I am forever grateful, love," Mia said.
As Narcissa examined the ring with great interest, Andromeda chuckled from across
the table, causing her to look up. "What's so funny?"
"That ring has been passed down to every wife of the House of Black in a single
line. Violetta Black was a Bulstrode, and before her, the ring belonged to Ursula Black,
who was a Flint."
Narcissa finally joined her sister in quiet laughter.
"Generations and generations of pureblood Slytherins and blood purists, and the
ring ends up in the hands of a Muggle-born Gryffindor," Andromeda said in amusement.
"Given to her by the last heir of the House, who has been blasted off the tree."
Sirius could not have looked prouder.