Each wave rolls its loot once, at the level of the enemy that died last. A roll picks a rarity from a table that moves from level 1 to 70 (more nothing, fewer commons, legendaries from level 10), and Magic Find plus the map bonus on Nightmare and Inferno multiply the uncommon, rare and legendary weights. Details and the tables are in the loot guide.
Wave Map Difficulty, Magic Find, %, Gold Find, %, and Potion Find, % for an Offline character (Solo Self-Found).
Enemy level 70 , map level 70 . Loot rolls once per wave, when its last enemy dies.
One item roll (1 per wave)
A legendary that drops here (not Back) is Ancient 10% of the time .
Everything else per wave
Can drop any of the following gems with equal probability: Polished Rhombus Amethyst, Polished Rhombus Diamond, Polished Rhombus Emerald, Polished Rhombus Ruby, Polished Rhombus Sapphire, or Polished Rhombus Topaz.