This is actually marble, I believe, but we did the best we could.
"I'm sorry, Peter. That was ungenerous and beastly of me. You shall give me something if you want to."
"May I? What shall I give you? Roc's eggs are cheap today."
For a moment her mind was a blank. Whatever she asked him for, it must be something adequate. The trivial, the commonplace or the merely expensive would all be equally insulting. And he would know in a moment if she was inventing a want to please him...
"Peter — give me the ivory chessmen."