how do the mineral occurs in eggness,sedimantory & mataur rock.
Answers
Chapter 5: Minerals, Rocks & Rock Forming Processes
When we discussed the beginnings of the universe, we noted the dropping temperatures were essential for the organization of matter as we know it. First the subatomic particles (quarks, electrons, etc.) were able to form, when temperature dropped further quarks were able to organize into protons and neutrons, then these were able to form simple atomic nuclei, and finally neutral atoms of hydrogen and helium could form when temperatures had dropped even lower. The remaining elements of the periodic table were produced via successive nuclear fusion in stars (up to iron), and under the intense pressures and temperatures of supernova explosions (up to uranium).
When the Earth and other planets accreted around 4.5-4.6 billion years ago, they contained a mixture of all the elements, and the relative abundances probably reflected the cosmic abundances indicated by spectroscopic studies. What happened to that mixture once the Earth started to heat up and differentiate? Basically, whenever chemical elements (atoms) are brought together there is a tendency for them to react with each other and to form compounds. How this works exactly is the subject of thermodynamics or physical chemistry, a subdiscipline of chemistry. Thermodynamics allows us to calculate the outcome of chemical reactions when we bring certain substances together.
What kind of compounds form in a given mixture of elements depends in part on their relative abundance, and in part on whether a given combination produces an energy-releasing reaction (exothermic, for example when gasoline combines with oxygen and explodes), or whether it requires energy input to react (endothermic, for example the synthesis of ammonia from nitrogen and hydrogen).
The material that was displaced into the mantle during formation of the iron core contained abundant oxygen, silica, magnesium, iron, aluminum, and calcium (plus smaller quantities of a range of other elements) and under the pressures and temperatures that prevail there, chemical reactions (following the laws of thermodynamics) produce compounds that are known as olivine and pyroxene. During formation of the crust, other compounds, in particular feldspars and quartz were common reaction products. The atoms and molecules in these compounds are present in compound-specific proportions, and they are not randomly distributed. Instead, they show very specific geometric arrangements. These compounds that make up the crust and mantle are commonly known to us as minerals.
Minerals, the building blocks of rocks, are inorganic solids with a specific internal structure and a definite chemical composition (varies only within a narrow range). They can form under a variety of conditions, such as:
A) during the cooling of molten materials (steel, from lavas, igneous rocks).
B) during the evaporation of liquids (salt, sugar, reference to evaporites)
C) the cooling of liquids (saturated solution)
D) at high temperatures and pressures new crystals may grow in solid materials (diamonds from coal, metamorphism)