Search results
Results from the WOW.Com Content Network
In mineralogy, an inclusion is any material trapped inside a mineral during its formation. In gemology , it is an object enclosed within a gemstone or reaching its surface from the interior. [ 1 ] According to James Hutton 's law of inclusions, fragments included in a host rock are older than the host rock itself.
Geothermobarometry relies upon understanding the temperature and pressure of the formation of minerals within rocks. [1] There are several methods of measuring the temperature or pressure of mineral formation or re-equilibration relying for example on chemical equilibrium between minerals [1] [2] [3] or by measuring the chemical composition [4] [5] and/or the crystal-chemical state of order [6 ...
Mineral inclusions (poikiloblastic texture): [17] a mineral that is formed at a lower P-T condition is included in another mineral that is formed at a higher P-T condition. For example, in thin section examination, biotite crystal is included in a garnet grain, so biotite is considered to be formed at an earlier time.
A study of sodium-rich quartz-alkali feldspar—biotite gneiss granulite facies terrane in the Kerala Khondalite Belt near Manali in south India found that in situ leucosomes (light colored segregations) within the gneiss showed the development of garnet replacing the dark biotite. The study indicated localized melting or migmatization within ...
Hydrothermal ore minerals, which typically form from high temperature aqueous solutions, trap tiny bubbles of liquids or gases when cooling and forming solid rock. The trapped fluid in an inclusion preserves a record of the composition, temperature and pressure of the mineralizing environment. [1] An inclusion often contains two or more phases ...
A conoscopic interference pattern or interference figure is a pattern of birefringent colours crossed by dark bands (or isogyres), which can be produced using a geological petrographic microscope for the purposes of mineral identification and investigation of mineral optical and chemical properties.
The timing of mineral crystallization can be used to categorize diamond inclusions into three types: protogenetic, syngenetic, and epigenetic inclusions. [14] Minerals in the protogenetic inclusions were crystallized earlier than the diamond formation. The host diamond encapsulated pre-existing minerals during its crystallization.
When a rock undergoes partial melting some minerals will melt (neosome, i.e. newly formed), while others remain solid (paleosome, i.e. older formation). The neosome is composed of lightly colored areas (leucosome) and dark areas (melanosome). The leucosome lies in the center of the layers and is mainly composed of quartz and feldspar.