90% of the world’s silk comes from Bombyx mori larvae, which feed on mulberry leaves. This type of silk is called mulberry silk.
Mulberry silk threads are the strongest and smoothest type of silk. In fact, a mulberry silk fiber is stronger than a piece of steel of the same length and diameter.
It can also hold moisture very well. It can hold 1/3 of its weight in water without feeling damp. This means that it won’t mildew or require airing out.
It’s considered the highest quality silk, and is measured in three grades.
Grade A silk is the highest quality raw silk. It is unraveled from the cocoon in long strands. Mulberry silk provides the longest silk strands, which allows for higher quality weaving. Grade B silk is next.
This silk comes from cocoons that didn’t develop properly. Grade C silk actually comes from the inner portion of the cocoon. It often has a yellow color instead of a white sheen, and has shorter fibers.