Pokémon Go players have been buzzing lately over this new kind of trait: Lucky Pokémon.

First discovered by data miners, fans were clamoring over what exactly a lucky Pokémon was. Though thanks to a recent blog post by Niantic, we now have the full scoop.

Whenever you trade a Pokémon, it has a chance of becoming “Lucky.” The longer you’ve owned that Pokémon, the more likely it is to become lucky. Lucky Pokémon require less stardust to level up. This incentivizes trainers to invest their time in lucky Pokémon over normal ones, in turn, incentivizing trades.

You can tell if a Pokémon is lucky by whether or not it sparkles and shines in the Pokédex menu. Too bad “shiny” is already taken as a term.

Niantic also announced that trainers will now earn XP when sending gifts, and the recipients are more likely to get larger numbers of stardust.

Well, better get trading.