That one depends on what you wanna use it for. Those crystals hold a lotta power packed into ‘em from all the emotion drops they’ve collected over time. If you know how, you can even use them to boost your dunamis if you need to.

Most people give ‘em to the arehtei, though. They seem to appreciate it, and it seems it nets you a vision of home if you do… But I can’t say what it’s like, seein’ as I’ve kept all mine.