Petrographic Modifications

Certain petrographic modifications of the rocks can guide the search of minerals because they are in direct relations with the occurrence of useful minerals that have formed in the same moment and due to the same cause of these modifications. For example, the impregnation of the schist tourmaline often times shows up close to aluminum deposits. CAOLINIZACION especially in the acid eruptive rocks (granites etc) as well as batholiths and laccoliths, often times comes with Sn and also in many cases characterizes the presence of auriferous veins. Dolomitization, of calcareous rock sometimes characterizes the presence of calamine, of hematite and of manganese oxide in limestone. Propylitisation, which is a type of hydrothermal alteration that most of all affects magmatic volcanic rock, that becomes green and can be brittle, with the development of batholiths and laccoliths often times epidote and in certain cases, mineralization with Au, Ag, Pb, Zn, Cu.

In the case of discoveries of interesting mineralization, a percentage of the different useful minerals needs to be indicated and how the mineralization presents itself, the gangue and the outside of the rock; vein that follows a fracture or according to the stratification, impregnations of the rock of useful mineral with or without gangue, stock work, nature of the contact between the vein and the covered rock, existence of possible salband, contact of faults between terrains that have a different nature etc.