Carved Owl Figurine Unknown material

I purchased this on eBay about 15-20 years ago when I was collecting owls.  It was in a lot from the estate of an elderly woman who had collected owls for her lifetime according to her son, the seller.  He stated at the time that he had no idea what it was made of.   I think it is perhaps a resin or plastic.  Perhaps a stone?  It is solid.  It weighs about 3-4 pounds.  It has carving marks on it.  It stands 10 inches high.  It is mostly green, with white and reddish brown veining.  The base may be a separate piece that was  somehow  bonded.  There is some dust I missed clearing under the tail that is  showing in the photos.

I haven't been able to find anything like it.  Any information would be most appreciated.

Fair