Sound light electro magnetic waves all have the same frequency wave patterns.
When a car comes towards you it sounds loud and gets louder because the wave frequency is getting tighter as it approaches. As it passes the waves continue to get tighter and you gradually can’t hear them.
In Spectroscopy these wave lengths have colours, so where the wave lengths are furthest apart these are gamma waves where they’re tighter that’s microwaves.
Each mineral gives off different wavelengths in an electromagnetic survey so these can be pinpointed.
Looking at the night sky stars give off different wave lengths so appear as the colour of their dominant mineral. Also because of the wavelengths it is possible to calculate whether they are travelling away or towards us.
In electro magnetic surveys they are looking for certain frequencies indicating mineralisation.
Only drilling though can tell you what’s down there for sure.