A conversation with HaChosenOne got me thinking about Yero's diamonds. That, paired with my vivid mental image of Elphaba wearing the necklace described here produced this little bit of fluff.
"I bought you something."
He could see her reaction in his head before he even said it, but he said it all the same. Yes, there was the eye roll, right on cue. "No, Yero. I don't need any gifts."
But he could be as stubborn as she was, when he wanted to be anyway. "Wait, this isn't for you. It's a gift to me. I just want you to wear it."
He realized how that could sound. Now she raised her eyebrows, clearly with her mind in the gutter. "You bought me something to wear?"
He grinned, but shook his head. "Not like that, love." He cocked his head. "Though that does give me ideas."
She playfully swatted him, but laughed. He loved her laugh, it was free and positively joyful. Good to see on her. "Will you let me show you or not?" She froze up, hesitating. Eventually, she nodded, looking slightly weary.
He took a small box out of his pocket. "Close your eyes," he instructed, and she obeyed. She could feel him push her hair off of her neck, feel him kiss the back of her neck, gently. Then he must've remembered his task, and she felt him clasp something against her neck. "Open 'em," he said.
She did, looking at the necklace he had placed around her neck. On a long, white gold chain hung a blue pendent, shaped like a diamond. She smiled, tracing her fingers over it. She turned to him, touching one of the blue diamonds exposed by his shirt, open at the neck. It was a perfect match, the right shape, the right color. "It's beautiful. But how is it a gift for you and not for me?"
He was smiling, pleased she wasn't rejecting the necklace. "I hate being separated from you. If you wear that, I'm always with you, so I'm always happy. So you can see how it's a gift to me- I get to be with you, always."
She wrapped her arms around his neck, leaning her head against his shoulder. "Is that a promise? You'll always be with me?"
"If I have any say in it."