a hard mineral used especially in powder form for polishing things and making them smooth 金刚砂，刚玉粉（尤以粉末状用作磨料） Oxford Collocations DictionaryEmery is used before these nouns:- board
Word Originlate 15th cent.: from French émeri, from Old French esmeri, from Italian smeriglio, based on Greek smuris, smiris ‘polishing powder’.