"Gryphon Emerald in Glass Case" Dragon's Lair (Ruby Spears) animation model sheet

It may not be a high-end collectible from the elite talents at the old Don Bluth Animation Studio, but here's a piece of officially licensed Dragon's Lair animation art, via a humble Ruby-Spears model sheet of the Gryphon's Emerald from the 1984 episode "The Girl from Crow's Wood."

Referred to in-episode as "The Gryphon's Stone", this magical object is the key to unleashing the villainous Sybilla, who hypnotizes a peasant girl named Bronwen (a doppleganger of Princess Daphne) into retrieving the Emerald for her. At the end of the episode, Dirk the Daring destroys both the Emerald and Sybilla.

This model sheet is painted artwork on an acetate cel layer, stapled over a blank piece of paper. I can't be sure if it is THE original sheet or one of several copies used by the studio of animators, but I can't imagine they would waste time and resources painting multiple copies, so odds are that it's unique.