Acelon was a rare pearlescent material found within the ice caves on planet Trill. Acelon was used extensively in Trill's ruling council chamber for the speaker's podium and the desks of the individual council members. Acelon was also used by the L'Dira as a component in much of their technology. When they exhausted the supply of acelon in their home system, they went to other worlds in search of the material. In 2075, they attacked Trill, taking large quantities of unprocessed acelon from a processing plant in Leran Manev. (DS9 - The Lives of Dax short story: "First Steps")