This is the only crystal, that I know of, that does what a person needs it to do when they get it.  As the person moves up levels, the crystal moves up with the person to continue helping them.
 
1 - 1.25" x .25" x .25" $20.00
2 - Sold
3 - Sold
4 - 1.5" x .25" x .25" $15.00