Duck Planter

This Duck was given to me as a wedding gift from my grandmother. It has been sitting around the house for over 35yrs. I don't know what it is made of, but it turns black very fast after it is cleaned ( pics do not reflect it as cleaned, it was not ). There is an I.D on the bottom as : JB2492 It has very detailed etchings on the wings and feet as well as the eyes. I am curious as to it's origin and material it is made of. Will sell if worth it. Thank you,Robert