Then keep the case with the crack. You'll be happy knowing that it was the case the disk came in and "original." Every so often, I receive a CD I've ordered with some damage to the case. Sometimes it's a small crack. Sometimes it's broken tabs holding the disk in place. That's how it is with jewel cases.
Hey, someone in this forum was hesitant opening his mono version remastered box set! Apparently there's a fine line between being a "die-hard Beatles fan" and being just plain silly.