This is the coat of arms of Rugia under the duchy of Pommerania (16th century). It was introduced as the modern coat of arms of Rugia, Germany in 1993, with the addition of a crown in the crest.
The design is found in the coat of arms of the dukes of Pomerania in the 16th century (1571, 1605) 
The lower part of the historical coat of arms of the principality (14th century) was probably slightly different, showing chevrons rather than bricks. 
This is based on a 19th-century description of a seal of the period ("vierfach stufenweise gesparret, roth und blau"). 
[1]

Herb Księstwa rugijskiego
Own work
Poznaniak