Silk postcards were a higher priced, more ornate way to send a special greeting in the early 1900's. Often the clothing of the people were made out of bright colored silk fabric that was then attached to the paper post card. The most collectible silk cards are the ones that have maintained their bright colors and show no wear.
Here is an example of an antique silk New Year's Post Card.
May the blessing of Health and Joy abide with you this New Year.
Your friends at Reuzeit Emporium.