These insulators were irradiated by Dennis McHenry (Metallurgist) at the Rock Island Arsenal in the late 1960s. Dennis made them as novelty items for friends. A few years after the fact, when Dennis realized these altered insulators were occasionally being circulated/sold as authentic, Dennis wrote the following article for CJOW: https://www.cjow.com/archive/article.php?month=4&a=04Cobalt-60%20Irradiation.htm&year=1972
Normally I do not sell altered insulators but these were part of his early experimentation. Dennis passed in 2013. Colors are similar to copper & iced tea.
$40 includes shipping.