Antique 18th Century Silver Double Headed Eagle Russian Or Austrian

Antique 18th century large silver pendent or order? Extremely well made of fine filigree work in the form of the crowned double headed imperial eagle (possibly Russian or Austrian) with an integral suspension loop, the obverse adorned at the center with a small gold medallion depicting the charging Knight (Saint George?). Reverse side of the eagle is set on the chest with a large dark blue cabochon paste. 

 
CONDITION: In very good condition with nice old patina. 

 
MEASUREMENTS:
 

 Height: 11.3 cm (4.45 inches)
 

 Width: 7.1 cm (2.76 inches) 

  
WEIGHT: 40.5 grams (1.43 ounces)