The petrography It is a branch of geology in charge of the study of rocks, focused on determining their components, describing their properties and classifying them. This discipline arises with the objective of identifying and explaining the elements that are present in nature and that influenced the formation of the earth, among which rocks can be included..
Various discoveries and studies laid the foundations for its establishment as a science, including the invention of the Nicol prism, a device that made it possible to convert normal light into polarized light with the use of crystals..
The contributions of scientists are decisive, such as Camille Sébastien Nachet, who carried out the creation of one of the first petrographic microscopes. Likewise, the first analyzes of the rocks with the use of the microscope carried out by Sorby in 1849 constituted a great advance for the discipline.
All these studies made it possible to classify rocks by groups and describe their main characteristics, such as textures, structures and composition..
The knowledge of minerals, the discovery of those that form rocks and their constitution is possible thanks to the invention of the petrographic microscope.
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Since ancient times, man has been interested in the knowledge of the elements that make up his environment; one of the great questions has revolved around determining how the earth was formed.
In order to study the composition as well as the properties of the elements that make it up, special emphasis has been placed on rocks, which gave rise to various branches of geology, including petrography..
The beginning of petrography as a science is related to the results of the research of scientist William Nicol, who in 1828 created a method to generate polarized light from small rock crystals..
Later, in 1833, Camille Sébastien Nachet, a French scientist, made one of the first petrographic microscopes and began studying rock crystals with the use of this device..
Henry Clifton Sorby was noted for his contributions through the experiments carried out with small rock minerals on the petrographic microscope in 1849.
Sorby's work was a starting point for the study of rock minerals through the microscope, and for the advancement of science since it motivated other scientists to use this device in their research..
One of the main exponents was Zirkel, who in 1870 carried out a study on basalt rocks in which he included the use of the microscope and managed to popularize it within the scientific circle..
Petrography, through the use of the petrographic microscope, is responsible for the study of rocks from a descriptive point of view. However, before being subjected to the study, the rocks go through various processes, the starting point of which are the field notes taken through observation..
Before entering the microscope, they are reduced until obtaining thin and very small slices to allow the light to pass through them, all with the purpose of determining their various components..
The study of rocks in petrography is carried out to determine the elements that comprise it, such as texture, structure and composition..
This discipline also focuses on the analysis of the minerals that are part of the rocks, which are distributed according to a specific order.
In addition to the analysis of its components, it also classifies the minerals found within these by means of polarized light in the petrographic microscope..
It should be noted that petrography includes a meticulous analysis of the elements that is not done at random; This is attached to the scientific method in order to provide knowledge to geology.
It was a device created by the Scottish physicist William Nicol in 1828, whose main contribution to the development of science was to lay the basis for the development of the polarized light microscope.
The scientist, in his experiment, used two pieces of a mineral known as Iceland spar crystal, characterized by the absence of color and its great transparency.
Another of the properties of this mineral is the double refraction that allows the ray of light that passes through it to be divided in two. Nicol took the pieces of spar from Iceland and put them together with balsam from Canada.
Canada balsam or balsam fir oil is a fluid obtained from a species of tree called Abies balsamea, which can be found in Canada and the United States..
The device made by Nicol is responsible for transforming the natural light that passes through the crystals into polarized light, which is reflected linearly towards a specific point.
His contribution served as the basis for the subsequent scientific development of various disciplines that used the microscope in their research..
With this name was known one of the determining investigations for the birth of petrography as a science, conducted by Henry Clifton Sorby.
This scientist developed a method that allowed to analyze the rocks under the light of the microscope in order to study their properties, as well as their origin.
The beginning of these works was in 1849, when Sorby arranged part of a rock on the microscope in order to determine its structures, but these results were not made known to the scientific world until 1858..
In 1858 Sorby exhibited his work, with which he achieved a great impact on other academics who followed in his footsteps and made great contributions to the development of petrography..
The experiment consisted of making fairly thin cuts to a rock and then that slice had to be fixed to the microscope slide, which at the moment of turning on the light would allow observing the entire structure of the stone.
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