To be distinguished from the above is the term “mat” in glass-painting or gilding, meaning dull, unpolished or unburnished.
Gold-leaf gilding, even if it is unburnished, is infinitely more brilliant than either gold paint or shell gold.
early 14c., from Old French burniss- present participle stem of burnir, metathesis of brunir "to shine, gleam, sparkle" (trans.), "to polish, make sparkle, make bright, shine," from brun "brown; polished," from a Germanic source (cf. Old High German brun, Old Norse brunn "bright, polished; brown;" see brown (adj.)). The connection to "brown" might be explained if the original objects in mind were wooden ones. Related: Burnished; burnishing.