Luca had given jewelry to women before, but it never meant anything to him.
Normally when he was trying to impress a woman, he could flaunt his wealth and that was enough. He would ask Rachel to retrieve something stylish and ignore the price tag.
However, for Sophia's necklace, he went out himself and browsed stores despite how the people were looking for him. At that particular jeweler, he was invited to a separate sitting room where he was able to drink tea casually while looking at their selection.
It was when he saw the emerald Alhambra that he found something that encompassed her eye color almost perfectly. That was the one he would give her and he didn't care about the price even though she was going to.
He sent separate messages to Rachel and Ethan to see if she would like something like that. Rachel said it was a timeless piece while Ethan said she would like anything he gave her.
It was enough for him to go through with it.