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           The Nature of Crystals
           Rob Erickson

           Computer Concepts, M-W-F, 2pm.
           Jim Zyla: Inst.

                    The Nature of Crystals
           R. Erickson
           Computer Concepts, M-W-F, 2pm

           Crystal - 'A homogeneous solid whose atoms or molecules are
           arranged in a regularly repeating pattern.
           Webster's New World College Dictionary

            In this article I will be discussing in brief some of the properties in the formation of crystals.  Let us begin with water as it it is used as a universal
           standard of measure and later, some other characteristics of minerals in general but specifically in regard to crystallization.  And finally some of the
           uses in that mineral crystals can be implemented.

            As in the case of ice crystals in the respect that conditions effecting their formation are physically manifested by two distinct behaviors as cohesion
           and compaction .   Cohesion is the action of crystals interlocking and cementing together, or sintering.  Compaction is the response of crystals to the
           environment by becoming more dense as time elapses.  Their influence is seen in all types of crystals.  The external factors that influence the action of
           compaction and cohesion form ten classes of water crystals.  Under laboratory conditions ice can be compressed to form Ice II through Ice IX using
           from 2000 atm.  up to and exceeding 350,000 atm.  (1 Atmosphere = 14.7 psi.).  Dr.  Holzapfel (German physicist) predicted that Ice X would be
           described as a very dense crystal structure that would not be made up of well defined molecules with hydrogen bonds but rather each oxygen atom
           would be surrounded by a tight cubic cluster array of nearest neighbor oxygen atoms and a hydrogen atom would be located between each oxygen
           atom so that one hydrogen atom is no more associated with one oxygen atom than another.   Whew, that was just about a mouth full!!!  Researchers at
          Argonne National Laboratory are compressing water under pressures of up to 670,000 atm.  When pressure is released ice reverts back to it's normal           form. Ice I is described as water. In each class there are six types of crystal forms; stars, plates, columns, needles, pellets, and fragments.

            From a chemical viewpoint the most fascinating things about water are it's unique properties.  The properties of water fall outside the normal
           range exhibited by compounds that are similar in structure.  It is the unusual properties of water that make it the key substance in the formation of life on
           this planet.

            Crystal forms show similarities throughout weather they be of frozen water, or other minerals.  They are the result of compression, condensation, or
           volcanism. All types are subject to the exterior forces of nature which act on their physical organization. Time changes matters form gradually
           through the action of metamorphism which is compounded by the other measurable forces. 

           The first is pressure caused by wind and water erosion piling layer upon layer thus increasing
           the weight on lower levels of strata.  In frozen water or other minerals pressure along with movement grind particles into smaller fragments.  Blending
           also occurs as different compounds mix together.  This can happen on molecular to glacial magnitudes.  Next is condensation, which is the settling of
           molecules on to a seed crystal from the atmosphere or from a liquid solution called a melt.  An added factor of change is temperature which
           combined with combinations of all ambient conditions, dictates the growth and decay of the specimen, depending on the elements or compounds
           present.  Low temperatures slow decomposition of chemical bonds and high temperatures increase decay.   Internal heat from the planet and solar
           radiation are sources of heat while planetary heat is lost to the frozen vacuum of space.  An (almost) never ending celestial cycle.

            The force of gravity is a measurable constant and so is predictable.  It is the cause of pressure and acts equally on all bodies relative to their mass.
           Ice is not the only material effected by external forces to a large degree because of it's observability where other minerals change slowly and lighter
           samples are too volatile.  Sublimation is the property of substances to evaporate without becoming liquid.  So, ice can sublimate quite readily
           compared to salt, but not as fast as frozen CO2 or hydrogen.  Ice and other crystals are considered to be visco-plastic, meaning they can change
           shape, sort of, to one degree or another, but not by themselves.  The mechanical influences acting upon minerals from physical disturbance brings
           about a change called 'age hardening'.  Crystallized minerals also have the ability to conduct and resist electricity and/or reflect and absorb radiation.

            The presence of salt in Earths water, measured in parts per thousand (ppt), decreases the temperature at which water freezes.  Fresh water reaches
           maximum density at 39.2`dF .(degrees Fahrenheit) and freezes at 32` dF.  The point at which the maximum density of salt water with 24.7 ppt. salt
           at the temperature of 29.61` dF. is final point at which density and salinity are different quantities. (see graph)

            Halite can be formed in lab experiments by heated a salt-water solution (melt), allowing crystals to condense into common salt as they cool.
           Some scientists think that large deposits of salt exist where prehistoric polar sea regions were previously located.

            Minerals are composed of elements and compounds that condense into crystalline solids with predictable internal structures with specific geometric
           patterns.  The aspect of replication is a fundamental property of crystals organization, indicating an order of arrangement at the atomic level.  In a
           solution of salt water halite crystals form when the melt is allowed to cool.
 
            If the control of conditions regulates the behavior of growth, than the nature and purpose of their use can be engineered to accommodate very
           specific applications.  Perhaps someday super high density memory elements could be manufactured in the zero gravity conditions of space using
           focused solar energy to fire the ovens that the heat ceramics they are made of.  People are always thinking of better ways to build things and tools
           are what we use to change our environment and make it more comfortable.

            A crystal can be, not only nice to look at but, functional as well.  A silicon molecule found in the quartz crystal is composed of oxygen and silicon
           (above), .its stable nature makes it a very predictable compound.  This type of silica, also happens to be immensely plentiful in the biosphere and is
           used in all sorts of ceramic products.  Crystal oscillators are used in modern electronic circuitry where accuracy of timing is critically important; they
           may be used in anything from a transistor radio, to a computer, to a communications satellite.  Silicates have selective frequency combinations and
           oscillation can be determined by inductance and capacitance. A crystal oscillator, like a tuning fork, can be tuned to specific frequencies. Resonant
           crystal oscillator circuitry is used all types of radio wave transmitters and receivers; (radio is actually a frequency band in the invisible light spectrum).
           An example of a tuned collector type resonant crystal oscillator circuit where a piezoelectric quartz crystal instead of a conventional type collector
           circuit is shown below.

            A more specific use for minerals are in that of semi-conductor devices such as silicon chips used in the integrated circuits (IC) of the
           microprocessors that drive modern computers. They also serve. in functions that perform logic operations and data storage in main computer
           memory, to name a few.  The field of micro-electronics includes all types of ICs which can be constructed from; an individual micro component
           construction = (Hybrid technique) and; b.-all components are constructed in a single structure= (monolithic construction).

            The chip making Process begins with a billet of highly refined glass, when after heating and cooling at precise temperatures, is cut into pancake slices
           called wafers that are then baked in a silicon dioxide (SiO2) atmosphere that encrusts the wafer with the prepared surface for the integrated circuitry.
           Then a coating of photo-sensitive emulsion is applied which is later exposed to ultra-violet light. The template for the circuitry (photo masking) is
           projected by the use of a precisely focused laser light process like that used in laser printers.  After exposure the wafer goes through a corrosive wash
           that removes the unexposed portions leaving behind the complex pathways the electrical impulses travel on there way to and from the each
           connection.  This process can occur a number of times creating layers which form the substrates in which the various values of specific inductance
           and resistance belong.  Through the result of diffusion, heating, baking, vaporizing, exposing, washing, depositing, coating, layering, (etc.) processes,
           individual or arrays of components are fabricated on a single micro-chip.  A two inch section of a wafer slice will yield 800 chips that measure 0.05
           inches square.  Thousands or tens of thousands of components can be installed on a single chip.  The circuit board is made with a similar photo-
           masking scheme, although on a larger scale and not quiet as involved or precise.  Then, after the protective coating of shellac is applied the
           semiconductors are attached by a machine soldering method.  After all production routines are complete the finished circuit board is ready for
           testing!!!  In the future it my be possible to produce chips from silicon wafers that contain logic and memory circuits that number in the millions and
           billions.

            And so, to summarize, from the simple to the complex we can see that the abundance and similarities of minerals and crystals cause them to be a
           diverse and useful building material.  Beginning with minerals in general like water and move toward more complex ideas like computers.  The
           purpose of this paper was to describe some of the ways things commonly found in nature behave and how they can be fabricated into sophisticated,
           high-tech hardware.
 

           BIBLIOGRAPHY
 
 
           1. The Avalanche Hunters - Montgomery Atwater
             ©1968 - Macrae Smith Co. - Phil, PA.

           2.  VanNostrand Scientific Encyclopedia
             ©1989 - VanNostrand Reinhold Co. - Ny, NY.

           3. American Practical Navigator - Nathaniel Boditch
             ©1962 - US. Navy Hydrographic Office - Wash, DC.

           4. Physical Geology - W.K. Hamblin & James Howard
             ©1964 - Burgess Pub. - Minn, MN.

           5. Bushsbaums Complete Handbook of Practical Electronics
             ©1981 - Prentice Hall Co. - Edgewood Cliffe, NJ.