Source : Webster's Revised Unabridged Dictionary (1913)

Sandix \San"dix\, n. [L. sandix, sandyx, vermilion, or a color
   like vermilion, Gr. ?, ?.]
   A kind of minium, or red lead, made by calcining carbonate of
   lead, but inferior to true minium. [Written also {sandyx}.]
   [Obs.]