Not Smart Guy

Sam was out shopping in the mall when he meets his friend Abe outside the jewelers. Sam notices that Abe has a small gift-wrapped box in his hand. "So what have you just purchased Abe?" Sam asks.
"Well, now that you've asked," replies Abe, "it's my Rifka's birthday tomorrow and when I asked her this morning what she wanted for her birthday she said, 'Oh, I don't know, dear, just give me something with a lot of diamonds in it.'"
"So what did you get her?" Sam asks.
Abe replies, smiling, "I bought her a deck of cards."