Gems are a mineral, typically crystalline in nature that are used in either a industrial capacity or as ornate gemstones/jewelry for adornment.
Gems are a resource the is used for expensive tech like personal shields, occult powers and jump-gate construction. It is also used in other applications.
Gems can be used in the construction of Luxury Items
Gems can be fund during Adventure & Exploration.
Gems can be mined via Gem Mine.
Gems can be sold on the Public and Black-Market