Anyone Using Crystals?

I have been experimenting with tourmaline and some of the ideas mentioned in this thread.  I have heard some very good results, so thanks for all the ideas Geoff and @mahgister and others.  One thing I didn't see above (but I could have missed something as there are many good ideas embedded above) is that it is quite effective to close off open USB and ethernet ports on modems/computers etc with crumbled tourmaline powder pressed onto bits of silicon caulking material.  I emptied tourmaline powder into convenient crevices in my main Verizon modem and also put a piece of tourmaline inside my Apple Airport Express which serves as router.  All of these tricks have been quite effective in improving my computer audio sound quality. I'll also be trying out some of the other stones/crystals mentioned here in time.

@agriculturist what color Tourmaline?

I used black tourmaline that I bought on eBay from the seller worldincensestore. He has both glossy black tourmaline rods and rough black rocks. I have both but can’t tell the difference sound wise anyway. Bits of the rough black rocks are easier to crumble, and you might find some small amount of powder in your shipment due to impact in transit.

I own a cheap RFI detector. Used mainly for AC power leaks.
I find if I coat small quartz crystals with dielectric grease (like a car motor stuff) Then place the crystals in a baggie and press them down tight, the baggie of crystals totally block RFI from an AC outlet.
If the crystals are left loosely packed, they do NOT block the RFI.
Others use some juice and then have to bake the crystals.. My method with dielelctric grease need no baking.
(though you NEVER want to get dielectric grease in an eye!)

I tried them $100 worth of small various types of white, pink, green, purple brown quartz. I am pretty bored with it though. The result is too small to bother much anymore.
I am just mentioning the blocking effect with packed quartz.

I am finding the biggest impact of using black tourmaline around the fuse box. The effect is on naturalness and coherence overall, and bass and mid-range. I was surprised by the sharply different effect I got from a piece of red agate in treble output around the fuse box, and am now very happy with a combo of the tourmaline and agate there. And then I have tourmaline rocks now sitting on most of my AC cable ends and in total they have a nice impact. As noted above by others placement does seem to matter. I want to try the tourmaline inside my balanced power transformer conditioners next, maybe next weekend.