Final answer:
Metal sulfide is the most commonly found sediment deposit around hydrothermal vents.
Step-by-step explanation:
The sediment deposit most commonly found around hydrothermal vents is metal sulfide. Hydrothermal vent fluid contains minerals of metal sulfide, which are released into the surrounding water. This sediment deposit can serve as a rich source of chemical energy for microorganisms and can support thriving communities of animals.