old unicorn fairy tale. Opals?

[ManaMinori 4,145]

While browsing dA, I came across a beautiful picture of a unicorn, and upon reasing the description, it mentions taking inspiration from an old fairy tale about this rare breed of unicorn called Opals. 

http://www.deviantart.com/art/Opalescent-Amircorn-371556755

While the artist comments provide links to the site that had information on these unicorn Opals, it has apparently long since been dissolved into internet dust, and deletion. 

Is there anyone who might be familiar with ancient folklore, specifically unicorn fairytales, to provide any info on these rare "Opals" unicorns? 

Edited January 17, 2017 by Nightmare Muffin