Amber

Amber is a type of Gem. Besides Orange Torches, Crate Potions and Amber Gemspark Blocks, it cannot be used to make anything else other gems can be made into, such as Grappling Hooks or Phaseblades. It can however be placed as a decoration like the other gems.

Unlike other gems, amber cannot be mined, and can only be acquired by feeding silt and slush into an Extractinator.

Trivia

 * Amber's original purpose, the Orange Torches, were apparently added because of a "really persistent nagging brit."