In Season 3, players will need to acquire the Spark of Dreams profession crafting material in order to upgrade their crafted items to higher items levels. However, in order to combine 2x Splintered Spark of Dreams into a Spark of Dreams in Patch 10.2, players will expend 250x Flightstones as well.
Early datamining suggests that it initially costed 30x Drake's Dreaming Crests, but Flightstones should be a better option that doesn't require the exchanging of crests or specific content.
This extra reagent of Flightstones is an additional requirement compared to the Season 2 Spark of Shadowflame, but should be easily obtainable especially due to the abundance from new Emerald Dream Superblooms & World Events coming in 10.2.
Superblooms & Patch 10.2 World Events Preview
The rate at which players acquire Splintered Spark of Dreams has not yet been confirmed, but we suspect it will follow a similar biweekly pacing similar to Season 2. You'll likely receive your first one from Dreams Unified similar to Power Unified and then subsequent ones from the weekly quest A Worthy Ally: Dream Wardens similar to A Worthy Ally: Loamm Niffen.