The Gem Hoarder
The Gem Hoarder, Shen's Bane is a variant of the Treasure Goblin in Diablo III, introduced patch 2.1.2.
They always drop a bunch of Gems when killed: 20-25, of the usual quality for the appropriate level. These gems have a higher chances for Imperial quality at level 61+, and at least some of those are guaranteed to be Imperial.
They also drop gems while running, but provide no other loot at all upon death.
Gem Hoarders have a diamond-like appearance to distinguish them from normal Treasure Goblins, the same model as that of Snitchley.
Treasure Goblins: Blood Thief • Gelatinous Sire • Gem Hoarder • Gilded Baron • Insufferable Miscreant • Malevolent Tormentor • Menagerist • Odious Collector • Rainbow Goblin
Treasure Realm: Vault Peon • Vault Sentry • Baroness Greed
Other: Snitchley • Herald to the Queen