possibly from Ashur, a finely detailed bull-calf carved of mottled red-brown agate with gold loop around the body.  
For a very similar example and discussion see:  Maxwell-Hyslop, K.R. "Western Asiatic Jewellery" (1971) page 177 ill. 111 
Condition: Intact and in excellent condition.  Museum quality, a rare and exceptional example.
Dimensions:  Length:  1.5cm  (5/8")  Height:  1.5 cm (5/8 inch)
Provenance: Vernon Pick private collection, acquired in the late 1950's.