Good Question. Not sure this is right...but sometimes supersaturated solutions will crystallize out if you tap gently on the external surface of a test tube, or expose them to mechanical shock, like banging them down on the desktop...kind of like nitroglycerin. The clicker that initiates the crystallization in the device supplies two things...nucleation sites, and a slight mechanical vibration simultaneously. When recooling the saturated, already used once solution, there is an absence of vibration...perhaps that's the patent, too.
edit: Aha! Garnet is also piezoelectric. Outside the clicker there is no effect on cooling. A little jolt to some blasting gelatin produces quick results, though.

I once made a tiny quantity of shock sensitive explosive, and was drying it on a watch glass. A student using the pencil sharpener during a quiz, set it off with the grinding, from ~ 10 feet away. The custodian found several specks while sweeping the floor. Never made it again. It was also photosensitive. Training teacher never told me that part of the recipe.

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A third rate theory forbids.
A second rate theory explains after the fact.
A first rate theory predicts.
A. Lomonosov