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* Method of crystallization of solutions
Minerals are formed from solutions in several ways, the most important
of which are:
1- The slow evaporation of aqueous solutions of salts: such as the
growth of cubic table salt crystals that separate during the slow
evaporation of a solution of sodium chloride NaCl, as happens in saltines
dnd lakes with high salinity, such as the Dead Sea.
2- The reaction of the solutions with each other, such as the formation
of barium sulfate (barite mineral) as a result of the interaction of two
solutions of calcium sulfate and barium chloride.
3- The reaction of a gas with a solution, such as the reaction of copper
sulfate with hydrogen sulfide gas, then the copper sulfide is deposited in
the form of the mineral Covellite. This occurs in mines where water seeps
into it, carrying sulfates of some metals, such as copper or iron.
4- The reaction of a solution with a solid, such as the reaction of zinc
sulfate with calcium carbonate, to form zinc carbonate (smithsonite) and
calcium sulfate.
Crystal definition:
A crystal is a solid body of homogeneous composition and has a specific
atomic structure defined by surfaces or natural planes between which are
defined symmetry relationships.
The surfaces that determine the outer shape of the crystal are known as
the crystal faces, and their nature depends on the natural and chemical
conditions during the growth of the crystals. The crystal may reach a few
centimeters if there is no obstacle preventing its crystallization and