some people said old copper Lightning rod (it's copper ground rod part ) have radioactive and is valuable it's may be older more than 100 years
Copper isn't radioactive. In recent years people have been stealing copper from buildings for its value as scrap metal.
What an indictment on our education system. Unless the lightening rod is rare enough to be a collector's item (which it may be, people collect a lot of stuff nowadays), it's only worth what scrap copper goes for and one lightening rod isn't going to make you rich.
Copper has a whole boatload of isotopes, two of which are stable. All the rest have half lives between a few microseconds and a few hours, so an old lump of copper has long since eliminated all its unstable isotopes, which were rare to begin with.
