O57 Chalcedony & Calcite

O57 chalcedony & calcite from Crawford, Nebraska 

lime green chalcedony & red calcite known as watermelon rock due to its food appeal. 
3.6 ounces weight 3 1/2”x2” size responds best under midwave and shortwave. Whitish yellow response under longwave.  The purple response is an unknown mineral response.