Petrology

Petrology (from Ancient Greek πέτρος (pétros) 'rock' and -λογία (-logía) 'study of') is the branch of geology that studies rocks, their mineralogy, composition, texture, structure and the conditions under which they form.

[2] Igneous and metamorphic petrology are commonly taught together because both make heavy use of chemistry, chemical methods, and phase diagrams.

As the cuttings are circulated out of the borehole, they are sampled, examined (typically under a 10× microscope) and tested chemically when needed.

Petrologists also include the principles of geochemistry and geophysics through the study of geochemical trends and cycles and the use of thermodynamic data and experiments in order to better understand the origins of rocks.

There are three branches of petrology, corresponding to the three types of rocks: igneous, metamorphic, and sedimentary, and another dealing with experimental techniques:

A thin section of a volcanic sand grain seen under the microscope, with plane-polarized light in the upper picture, and cross-polarized light in the lower picture. Scale box is 0.25 mm.
Ljudmila Dolar Mantuani (1906–1988), first female professor of petrography in Yugoslavia