From an unused root meaning to bleach, i.e. Whiten; white, i.e. Marble. See shesh.
see HEBREW shesh
H7893. shayish
שַׁ֫יִשׁ noun [masculine] alabaster (foreign word? Late Hebrew id.; Aramaic שַׁיְשָׁא , perhaps Assyrian šaššu ); — ׳אַבְנֵישֿׁ 1 Chronicles 29:2 (material of temple); compare PatrickHast. DB MARBLE.