Goblet of Eonothem (also known colloquially as "the cup", "the chalice", or just "the goblet") is an Artifact Piece in Genshin Impact. It increases a character's stats and currently has 11 possible main stats: HP%, DEF%, ATK%, Elemental Mastery, or Physical/Hydro/Pyro/Cryo/Electro/Anemo/Geo DMG Bonus%. Artifact Pieces can appear in all rarities (1-5 stars).
It is considered the hardest artifact piece to get "good stats" on because of the sheer number of main stats it can have and the rarity in which certain main stats can drop. Certain community-made experiments show the highest probability of main stat are DEF% (21%), ATK% (21%) and HP% (19%) while Physical and Elemental DMG bonus% have roughly 4-5% chance to drop each, and Elemental Mastery only has a 2-4% chance.