Rainbow Mayanite link to essence
This is a very difficult crystal to get and excrutiatingly expensive! Caireen, at Bluestone Vibrational Therapies has used one of my own personal pieces to create a fantastic essence which can be used instead of the crystal, or used as an essence. If you want to make a grid, you could ask a piece of clear Quartz to act as a surrogate and then put a drop of the essence on it.
Caireen has a shop on Etsy