I am not sure about the authenticity of this frog whistle I found. The most outstanding feature of it are these little iridescent specs all over it. I don't know what the specs are but they remind me of mica. If you do a search on "manganese specks antiquities" you see more information about it. I'm told that hydrogen peroxide applied is one test of age, but so far haven't found any of the right strength. I appreciate any thoughts.