Look at the back of the pin to date it. In the late 1800’s, early 1900’s, fabric for women’s clothing was heavier than it is today. Pins and brooches had clasps that extended beyond the pin. This was needed to attach the pin onto the fabric, so that it would stay in place. Pins that extend beyond the edge of the pin are a way to date the pin to the last century. The other method that you can use to date a pin is to look for C clasps. C clasps are open, they do not open and close, the way modern pins do.