Crystal Communication: Anata no Kami-sama wa Imasu ka?

is the first volume of the Crystal Communication light novel series, written by Yukiya Akatsuki and Illustrated by Poporucha. It was released under the Dengeki Bunko Imprint in June 2003.

Synopsis
"Would you like to have lunch with me?" "I don't mind, but why with me?" "Because it's crystal-colored" "Sui ...?" "Because you're crystal-colored, I want to share time with you." When I met a mysterious girl at the university entrance exam, I didn't realize that "something" had begun from that moment. The girl calls herself Kay, and to her surprise, she has a mysterious power ...! A mysterious love story, appeared.

(source: Amazon JP - Translated)