Sky: Children of the Light runs on a small stack of currencies that all look similar at a glance. The two most relevant to shard eruptions — Wax and Ascended Candles — work very differently once you look past the name.
Wax (also called Pieces of Light) isn't spent directly — it's collected from lit candles scattered through the realms, from burning Darkness Plants, from daily quest rewards, and from black shard eruptions, then forged into spendable Candles. Candles are what actually pay for cosmetics, expressions, and unlocks on a Spirit's friendship tree. In practice, "earning Wax" and "earning Candles" are the same daily grind — Wax is the raw collection step, Candles are what you end up able to spend.
Ascended Candles are not a bigger version of regular Candles — they're a distinct currency used specifically to unlock a Spirit's top-tier reward: a permanent Wing Buff. This applies to any Spirit whose friendship tree you've completed, not just Traveling Spirits, though Traveling Spirit items are also priced in Ascended Candles. They're also spent on a few other things, like resize potions.
You earn Ascended Candles from two places: the weekly Eye of Eden run (capped — see the reset guide for how that cap works) and red shard eruptions, which pay out anywhere from 2 to 3.5 Ascended Candles depending on which realm the shard lands in that cycle (full numbers in the red shard vs black shard guide).
"Candles" and "Ascended Candles" sound like the same currency at different tiers — they aren't. Regular Candles are earned constantly and spent on the everyday cosmetics/expressions/music any Spirit sells. Ascended Candles are earned slowly and spent only on the expensive, top-tier unlock at the end of a Spirit's tree. Saving Ascended Candles for the wrong purchase — or not realizing you need them at all for a Wing Buff — is the single most common currency confusion for players still learning the game's shop system.
This is why the two shard types pay out differently: black shards give a flat 4 Wax (which becomes Candles) since they're the frequent, low-risk eruption, while red shards give the rarer Ascended Candles precisely because they're harder to get to — Dark Crab included. Check today's shard to see which one is up next.