Plaustrite Shards are a resource you will need in Genshin Impact to make Xiao Lanterns. It is not hard to find, dropping from any piece of ore that you farm in the game. To be efficient about it, you want to find areas that have lots of ore.
People normally farm very specific ores that they need, but for this guide, we are just focusing on areas with a high concentration of ores, regardless of the ore type. Farming these spots every couple of days should keep you with more than enough Plaustrite Shards to get through the event.
Directly south of Mt. Tianheng, you will find 12-15 different farmable ores. Make sure you check both sides of the valley here.
Guyun Stone Forest
Spawn at the domain and head west, and you will come to a big boulder with 6-7 ore deposits. Continue down the chain of islands and turn left and you will find 7-8 more.
Mingyun Village is a great spot for mining ores. Make sure you check all the smaller caves in the and around the village.
Spawn at Mt. Hula then drop down to the visible Cor Lapiz deposits. Grab them then go right to the pond, and down the small path. You will find more ore all along the path, and along the cliff on the right.
To the south of the Oceanid boss fight is a path that cuts through the cliffs. You can find lots of different types of ore here, and plenty of Plaustrite Shards.