Trinium (also called ke) is an element that is a hundred times lighter and stronger than steel when refined. It is also referred to as an alloy.
Unrefined trinium is brittle and relatively useless. It can be strengthened for processing when put into a water saturating tank or found in a calm, moving river. Stargate Command attempted to mine a mountain of trinium on PXY-887, but the local Salish tribe asked them to stop, feeling that their methods were wasteful and destructive. However, the SGC was also able to locate another mine.
The power core of Apophis' new battleship was entirely encased in trinium. As a result it was shielded from a C-4 explosive device. Trinium is also a component in a compound used in a great deal of Tollan technology. After Earth's Stargate iris was destroyed by a black hole, the Tau'ri installed a new one made of a trinium-titanium alloy. Alloyed with Naquadah, trinium was an important part in the construction of the Prometheus and Daedalus-class battlecruisers. Asgard ships also uses this type of alloy with an addition of carbon. Fine-tipped trinium darts are capable of penetrating the soft part of Kull Warrior armor. Theoretically, other similarly sharp weapons would be effective against Kull Warrior armor.