This release is sort of elusive. It has no listed artist, and is a release Valley of The Sun did partnered with the Great American Audio Corp, a company which has long since disappeared from time. I found some info from it on a youtube video, and the inlay card says:
Musical sounds of relaxation.
Indescribably beautiful, incredibly calming, magical in their ability to inspire, balance and harmonize the listener, these are the soothing sounds of relaxation."
From the research I did online, it appears to have been released in May of 1989. There was no more info on it
besides its ISBN, which is 978-1-55569-296-4. My assumption is that this music was created by Robert Slap, since it is very much in his style. Aquamarine was the first Valley of the Sun music tape I ever heard, and it introduced me to this wonderful company. I decided to E-Mail the company myself to find more information on this elusive tape. Here is the response I got: