Pre-scintilla crystals form within cysts occurring underground with have the appearance of geodes. The crystals within fracture into scintilla upon exposure to air. Scintilla are harvested from ruptured nodules, though the nodules themselves may be excavated and carefully ruptured by hand, a process called "cracking." Cracking tends to yield more scintilla, but over lower value.
Despite claims by montebanks, no sophont of Gnydrion has every been proven to be able to detect pre-scintilla nodules. So-called scintilla-sniffing nonnigs however are able to do so, though how they do this is mysterious.
In addition to their pleasing, crystalline appearance, scintilla are favored as currency because they are impossible to counterfeit, even through use of magic. In fact, scintilla are minor magical insulators, absorbing and dissipating fae energy directed specifically upon them, turning black and cracking in the process.