We don't have synonyms for silver grain yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are silver gray, silver grass and silver stain.
(n) :
(botany) The lines or narrow plates of cellular tissue which pass from the pith to the bark of an exogenous stem; the medullary rays. In the wood of the oak they are much larger than in that of the beech, maple, pine, cherry, etc.
(n) :
(botany) The lines or narrow plates of cellular tissue which pass from the pith to the bark of an exogenous stem; the medullary rays. In the wood of the oak they are much larger than in that of the beech, maple, pine, cherry, etc.