This is an awesome piece I picked up at an estate sale.... 
From what I could find on the internet it is "green onyx marble" or alabaster. 
Clam shaped with a battery operated analog clock, made in Japan. 
Measures: 5.5" wide, 4" front to back, 3 " tall. 
It is not currently running, I'm assuming it just needs a new battery. 
Even not running it make a great collectible decorator piece! 

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