I HAD to buy this at the estate sale, as it is so different, and made very well, possibly made for the purchaser! No tag listing material or where made...but, instead reads, "Susana Laffayette, California" Size 8. Dry Clean Only. 

My best guess as to the fabric is linen blend. It has a hine to the finish, is very dressy and feminine, with the design fit. The flowers which remind me of postcards are bright color and so gorgeous.