Crystavis is one of the first words I created for New Zigon. One of my early concepts is that I wanted the characters to have a piece of jewelry (amulet and/or ring) that could help them focus their "power." I spent several weeks going through a Latin-English dictionary and using Latin translation and information websites on the internet, looking for words or parts of words that I could use. When translating "power," "force," and "energy," I continually came across the Latin word "vis," defined as "force, violence, STRESS, strength, energy, strain." I have used "vis" in several of my New Zigon terms.
Translating "crystal," I found words such as crystallum, crystallus, and crystallinus.
You shouldn't need to consult the Letter People to see how the word Crystavis came about!