Silk
Despite its reputation as a delicate fabric, silk is a hard wearing fibre. Silks have different weights and finishes, so depending on these factors the care instructions can change.
If in doubt, always dry clean. A silk satin (shiny finish to the fabric) will always be dry clean only to ensure the finish stays luxurious and soft. If wet, a satin finish will leave water marks and/or lines.
Silk twill and silk crepe can be machine washable (delicate & cold wash) and hung to dry in the shade.