You can get many more websites if you google up "crystal healing." Unfortunately, many are repetitive and base their information on Melody's series of books. So you might as well get her book(s) or Judy Hall's Crystal Bible which IMO is derived from Melody's work. You can easily find clean used copies from either Amazon.com or abebooks.com.
If you have a particular stone you want to find out about, google "stone-name crystal healing."