Hobson May Collection has dated this piece to the 1930s.
The two halves fit together well making the complete shell. There is a small chip to the inside edge of one half, this can be seen in the photos, the general condition is good.

This unusual and highly decorative clam shell came from a private collection and would be an eye catching and interesting display item.
c. 1930
Width: 8.25" 21 cm
Depth: 5.25" 13.5 cm
Height: 4" 10 cm
Hobson May Collection has dated this piece to the 1930s.
Decorative furniture and accessories from the 18th to 20th century
You can view the stock and full dealer information on the Hobson May Collection Profile Page