Beryllium is an alkaline earth metal, one of the basic atomic elements.
In its crystalline form, beryllium is a deep reddish purple color and slightly translucent. It is the standard currency in Grid 539 of the Delta Quadrant. There, even a small amount of the substance is quite valuable; several species would trade a large fleet of starships for a block of no more than a few cubic centimeters in volume. In mid-2376, Neelix traded Abbadon a few plasma couplings for a number of items including a beryllium crystal, although neither realized the value of the beryllium until Seven of Nine identified it amongst the otherwise useless trinkets. Neelix offered to return it in exchange for information about another object obtained from Abbadon, a ship called Alice, which had possessed USS Voyager helmsman Tom Paris. (VOY: "Alice")
- The crystal may have been the mineral beryl, which is a significant source of beryllium on Earth. The red variety is the rarest, and a gem-quality crystal is extremely valuable. (Metallic beryllium is opaque and silver-gray in color.)