I was thinking "I have an overexcitable 8 year old Armin who has already lost the ring once and it will get lost again in his pocket, and I don't want him to get upset again over it" The necklace was the thing that made the most sense at the time.
I should be used to the idea that anything I hand you becomes your property by now, shouldn't I? How many of my shirts are your nightshirts again, now?