Shown are the marks on the back of a Dansk Arbejde (Danish Handicraft Guild) skonvirke style brooch, a guild that many silversmiths and jewelers belonged to that promoted Danish made items.
http://www.imagebam.com/image/b0190950655807
The 830 mark indicates silver content, the DA logo is for Dansk Arbejde. I am confused about the "S" in the circle. Is it the Danish silver mark or is it a makers mark?
Typically a makers mark accompanied the DA logo. However there are no other marks besides those shown and the "S" does not look like other Danish silver stamps that I have seen.
I have exhausted my text and online research sources. Any direction would be appreciated.