The quality of silk is graded by letters: A, B, or C. • A: Grade A silk is the highest quality silk you can buy, as well as having the longest strands. • B:  Grade B silk is made up of shorter strands and sometimes a chemical process is needed to get the pearly white sheen of the fabric, unlike grade A. • C: Grade C silk is the bottom tier when it comes to quality and can feel rough when compared to A or B.  This grade would also take chemical treatments in order to achieve that lovely white sheen.