1990s - early 2000s fine ribbed knit duster by Kaat Tilley. Jute rapped buttons. Bustle back. 80% viscose 20% silk. 

Size Extra Small / Small - Labeled Small 
Bust: 34" a couple inches stretch 
Hips: 38" a couple inches stretch 
Length: 56" 

Condition: Great! 
- mend across front as pictured