Dear Jane,
I hope this will help some, it's not a prayer, but might help in your search.
Celestite is a stone from the angel realm that relates to creativity and communication it is peaceful and helps calm anger and tension. Balances energies, enhances dreams and is good for sleep disorders. It is often used on the throat and third eye chakras. The name comes from the latin Caelestis meaning heavenly, so it is said to help spiritual communications. Celestite or Celestine, sometimes known as 'angel's stone'. You can see how it could relate to Reiki.
Angels are communicators or messengers of God that are sent to us in times of troubles or heartbreak. Angels are a thought form of God, wrapped in a celestial (Heavenly) body we can accept. They literally bring the thoughts of God, as we know him, to us. The words or impressions we get from them are almost never worded the same way we would talk to ourselves. These thought transmissions pass through the Higher Soul of our spirit, to our intelligence, to get the message across to us. The higher soul is in touch with the God part.
Love in Light, Dearheart