Trillium, also known as Trillium Ore was an ore that was one of the hardest substances in the galaxy. However, it was highly toxic. Trillum ore was used to make Trillium Armor and shards thereof were shot at enemies by the Shard Reaper. The shrapnel in the Shrapnel Upgrade was made of shards of trillium ore. At the IRIS Supercomputer, Captain Slag warned his pirate crew that Trillium ore was toxic and was not to be taken orally at first. He then revised his words, saying it was best not to take it all. In Ratchet & Clank Future: Quest for Booty, Barnabus Worley stated that the bedrock on Hoolefar Island is full of Trillium ore and that it created too much electro-magnetic static for some ship, so that they had to use a Supply Beacon.
Trillium ore was mainly a Lombax resource, as it was mined primarily by them. Lombaxes used it in the Trillium armor and even discovered the egg of Emperor Percival Tachyon while mining Trillum ore. Kaden's father, Ratchet's grandfather, owned a Trillium Harvester, which Kaden used to fly to the Battleplex.