I found this button in the back yard of a house in town. There is no back on it, but it looks to have had a steel back that is completely rusted away. It is 1/4" high and about 9/16" diameter. I used an ultrasonic cleaner on it and it appears to be brass. Our local libraries do not have any copies of Alfreds' button book, so any help would be appreciated. Thanks! Festus.