Among the many kinds of silk fibers, mulberry silks are produced by the silkworms which are fed from the mulberry leaves (hence its name).
In order to gain silk from silkworms , we feed them with mulberry leaves for months. After they complete their life-cycle, they produce cocoons which are used to make silk fabric. It takes approximately 3,000 cocoons to produce half a kilo of silk.
Considering the time and effort to product mulberry silk, the price can not be cheap.