Healing crystals are very popular and curious things. People like to wear them as accesories, gift them, or even use them for theraputic purposes. The users of crystals do so with a belief that it enhances certain emotional/mental/physical aspects in them. Like an aid.
I realize its not really accepted by everyone, but there's a huge crowd who is interested in this. So a cane with a natural crystal holding part might be very intriguing for them. The more frequent the contact with the crystals, the better. So why not combine this motivation to hold a natural stone with the neccesity to hold a walking aid, thus change how people feel about it all together! One would be feeling good about it, since they feel it benefits them in many levels - and its an extra benefit, not a compensation. This is very important, since using an aid creates stigma due to it making people feel 'less' than others, wheras in this case they might feel 'more'.
The top part can be removable, or an extending part can be designed so that it can be added on to any cane, crutch or other walking devices.