He stretched out his hand, and in his palm was a pendant, a small aquamarine held in a cage of thin copper wire that was twisted to look like tiny leaves. Margie looked down at the exquisite little pendant and then at her waiting brother.

"I thought you could hang this on your chain," Rider said hopefully.

Margie took the pendant from him and let it dangle between them, catching the light.

"You really are just like Dad," she said smiling. Then she began to laugh happily and a little wildly until her eyes filled with tears.

Which sentence best shows the significance of Rider giving Margie the stone?