As metallic ores are found in every rock type. These get concentrated into the earth through the formation of basaltic lavas and further these minerals upon solidification from rocks of metallic nature and have magnetic properties associated with them.
Metamorphosed rocks have deposits of lead, magnesium, copper and iron and other heavy metals. Various gemstones also bear this type of element that is supposed to have occurred at the time of the formation of earth core and mantel.
Some were formed from aluminum and others by sandstone as due course of time extreme pressure and heat melted to form these deposits.
