The Collaborative International Dictionary of English v.0.48:

Erythrite \E*ryth"rite\, n. [Gr. 'eryqro`s red.]
   1. (Chem.) A colorless crystalline substance, C4H6.(OH)4,
      of a sweet, cooling taste, extracted from certain lichens,
      and obtained by the decomposition of erythrin; -- called
      also erythrol, erythroglucin, erythromannite,
      pseudorcin, cobalt bloom, and under the name phycite
      obtained from the alga Protococcus vulgaris. It is a
      tetrabasic alcohol, corresponding to glycol and glycerin.

WordNet (r) 3.0 (2006):

erythrite
    n 1: a reddish mineral consisting of hydrated cobalt arsenate in
         monoclinic crystalline form and used in coloring glass;
         usually found in veins bearing cobalt and arsenic [syn:
         erythrite, cobalt bloom]