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Topic: Crystal system


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In the News (Sun 19 Nov 17)

  
  The Isometric (Cubic) Crystal System
Of the seven crystal systems, the isometric system possesses the highest symmetry.
Keep in mind that cell parameters do not define the crystal class, but are a consequence of the symmetry elements that define the system.
Crystals usually have several forms, and can look remarkably different, depending on how pronounced each form is. The applet to the left and following applets show the progression from Cube to Octahedron.
www.iumsc.indiana.edu /morphology/cubic.html   (446 words)

  
  Crystal Growing K-12 Experiments for Lesson Plans & Science Fair Projects
Which crystal structure the fluid will form depends on the chemistry of the fluid, the conditions under which it is being solidified, and also on the ambient pressure.
A crystal structure is composed of a unit cell, a set of atoms arranged in a particular way; which is periodically repeated in three dimensions on a lattice.
The crystal systems are a grouping of crystal structures according to their basic symmetry characteristics, and each crystal system can be described by a set of three axes in a particular geometrical arrangement.
www.juliantrubin.com /encyclopedia/chemistry/crystal.html   (2408 words)

  
 Intro to Minerals: Crystal Class and System
(The rhombohedral lattice is a subset of the hexagonal crystal system.)
Crystals of this system tend to be of prismatic, tabular, or acicular habit.
It is thus apparent that the characteristic symmetry element of the isometric crystal system is the possession of four 3-fold axes of rotational symmetry, while the characteristic symmetry element of the rhombohedral division of the hexagonal crystal system is the possession of a single 3-fold axis of rotational symmetry.
dave.ucsc.edu /myrtreia/crystal.html   (4278 words)

  
 Crystalline Structures | Crystal Lattice | Crystal System
The crystal system is a grouping of crystal structures that are categorized according to the axial system used to describe their "lattice".
The Hexagonal crystal system is has four crystallographic axes consisting of three equal horizontal or equatorial (a, b, and d) axes at 120º, and one vertical (c) axis that is perpendicular to the other three.
Although a crystal structure is an orderly arrangement of atoms on a lattice, the order may be different along different directions or axis in the crystal.
www.khulsey.com /jewelry/crystalline_structures.html   (753 words)

  
 Cubic (crystal system)
In crystallography, the cubic crystal system is the most symmetric of the 7 crystal systems.
The system is composed of the three Bravais lattices whose symmetry group is that of a cube.
The point groups that fall under this crystal system are listed below, followed by their representations in international notation and Schoenflies notation, and mineral examples.
www.xasa.com /wiki/en/wikipedia/c/cu/cubic__crystal_system_.html   (91 words)

  
 Crystal Systems
If a mineral belongs to the isometric crystal system, you will be able to find four 3-fold rotation axes on well-formed crystals of that mineral.
If a mineral belongs to the orthorhombic crystal system, you will be able to find either three two-fold rotation axes (with or without mirrors perpendicular to them) OR only one 2-fold rotation axis that has two mutually perpendicular mirror planes parallel to it.
The triclinic crystal system has three crystallographic axes (a, b, and c), all of different lengths, and all at angles different than 90 degrees.
www.neiu.edu /~kbartels/CrystalSystems.htm   (657 words)

  
 Your Gemologist Study of the Seven Crystal Systems
The reason being is that the trigonal system is very close to the hexagonal system with the exception that the crystal surfaces are rounded somewhat to give a triagonal shape rather than a clean, well defined hexagonal or six sided shape.
This is where the debate lies regarding whether or not the trigonal system is a system into itself or simply a sub-category of the hexagonal crystal system.
This system is one of the least symmetrical of the crystal systems, Until now most systems had some form or symmetry, meaning as you turn the stone you would see the same shape repeat itself as the crystal turns.
www.yourgemologist.com /crystalsystems.html   (1432 words)

  
 Czochralski crystal growing system - Patent 5976245
In a single crystal growing component of the Czochralski crystal growing system according to aspects of this invention, the body portion can be used both as a carrier for the lower portion and also as a seed crystal for growing a single crystal from molten semiconductor material.
The seed crystal 212 includes opposed depressions 218 which mate with protuberances 220 of the lower portion 214 to retain the seed crystal 212 and the lower portion 214 together during use of the single crystal growing component 210 for single crystal growing.
The seed crystal 272 can be laterally spaced from the lower portion 274 by a gap 278, such that heat conduction between the lower portion 274 and the seed crystal 272 occurs primarily via the retaining pin 276.
www.freepatentsonline.com /5976245.html   (7959 words)

  
 External Symmetry of Crystals, 32 Crystal Classes
Two mirror planes cut the front and side faces of the crystal, and are perpendicular to the 2-fold axes that are perpendicular to these faces.
Note that you are not expected to memorize the crystal classes, their names, or the symmetry associated with each class.
Among the common minerals with pinacoidal crystals are: microcline (K-feldspar), plagioclase, turquoise, and wollastonite.
www.tulane.edu /~sanelson/eens211/32crystalclass.htm   (2006 words)

  
 Bob's Rock Shop: Introduction to Crystallography and Mineral Crystal Systems
A FORM is a group of crystal faces, all having the same relationship to the elements of symmetry of a given crystal system.
All the crystal faces present are the expression of the repetition of a single form having the Miller indices of {111} about the three crystallographic axes (remember those from the first article?).
Each face on a natural crystal (octahedral galena or fluorite are examples), when rotated to the position of the (111) face in the drawing, would have the same shape and orientation of striations, growth pits or stair steps, and etch pits, if present.
www.rockhounds.com /rockshop/xtal/part2.html   (1223 words)

  
 Rhombohedral crystal system Information
In crystallography, the rhombohedral (or trigonal) crystal system is one of the 7 lattice point groups.
A crystal system is described by three basis vectors.
In the rhombohedral system, the crystal is described by vectors of equal length, all three of which are not mutually orthogonal.
www.bookrags.com /wiki/Rhombohedral_crystal_system   (112 words)

  
 Crystallography
Crystal Groups and Classes - Crystallography groups are composed of 32 classes of symmetry derived from observations of the external crystal form.
For additional information on crystal systems, please review an excellent on-line treatment of this subject, the Introduction to Crystallography and Mineral Crystal Systems by Mike and Darcy Howard.
Example Crystal Morphology - To further illustrate these symmetry elements, the example crystalline forms for each symmetry class were constructed using Faces (version 3.7) by Georges Favreau for older browsers and a JAVA language program called JCrystal by Steffen Weber for the java-capable browsers.
webmineral.com /crystall.shtml   (403 words)

  
 Crystal Clean   (Site not responding. Last check: )
Crystal Clean enters the water softener resin bed with the salt only during regeneration and is completely flushed from the system and does not remain behind in the resin bed.
Crystal Clean’s superior effectiveness far exceeds that of the current acid based products on the market because it keeps your water softener working like brand new, even after many years of service.
Crystal Clean is the only water softener treatment that is specifically designed for this application.
www.terlyn.com /html/crystal_clean.html   (640 words)

  
 Crystal system   (Site not responding. Last check: )
Crystals that are essentially cube-shaped, like dice, with three pairs of sides the same length, breadth and height.
Some cubic crystals may have developed further into 8- or 12-sided shapes, but these still belong to the cubic system.
The crystals have three faces at right angles to one another, but only two are equal in length, breadth and height.
library.thinkquest.org /C005277/Crystal.html   (162 words)

  
 Crystal Systems
There are six crystal systems and although some count the rhombohedral or trigonal subdivision as the seventh crystal system.
The difference between the crystal systems is determined by crystallographic axes and angles.
The difference is that in the hexagonal system, the prism is six sided and in the trigonal system, it a three sided prism.
www.emporia.edu /earthsci/amber/go336/laird/systems.html   (220 words)

  
 Crystal System
Under ideal conditions, the result may be a single crystal, where all of the atoms in the solid fit into the same lattice or crystalstructure but, generally, many crystals form simultaneously during solidification, leading to a polycrystalline solid.
Which crystal structure the fluid will form depends on thechemistry of the fluid, the conditions under which it is being solidified, and also on the ambient pressure.
Depending on the type of system, a system can often be distinguished from individual machines, elements or processes of that system by thenumber, arrangements and complexity of those elements.
www.altvetmed.com /face/21462-crystal-system.html   (727 words)

  
 Bob's Rock Shop: Introduction to Crystallography and Mineral Crystal Systems
In the isometric system, all 3 crystallographic axes are at right angles to each other and are the same length.
Crystal forms in the isometric system have the highest degree of SYMMETRY, when compared to all the other crystal systems.
No crystal system even approaches a sphere's degree of symmetry, but the isometric system is often quickly recognizable because some of the forms and combinations of forms somewhat approach sphericity (or, at least, roundness), especially when the faces begin to be curved, due to the high degree of symmetry in the isometric system.
www.rockhounds.com /rockshop/xtal/part3.html   (2302 words)

  
 Reference.com/Encyclopedia/Crystal system
A crystal system is a category of space groups, which characterize symmetry of structures in three dimensions with translational symmetry in three directions, having a discrete class of point groups.
The 73 symmorphic space groups (see space group) are largely combinations, within each crystal system, of each applicable point group with each applicable Bravais lattice: there are 2, 6, 12, 14, 5, 7, and 15 combinations, respectively, together 61.
The crystal structures of biological molecules (such as protein structures) can only occur in the 11 enantiomorphic point groups, as biological molecules are invariably chiral.
www.reference.com /browse/wiki/Crystal_system   (716 words)

  
 LATENT HEAT OF FUSION-UNIT CELL-CRYSTAL SYSTEM
All the unit cell of a crystal are identical.
Length of edges (axes) and the angle between the edges are collectively known as "Cell Parameters".
In this system, two sides are equal but third side is different.
www.citycollegiate.com /solid.htm   (220 words)

  
 MSA's Rock'n Internet Site--Crystal Systems
The study of crystals and the laws that govern their growth, external shape, and internal strucutre is called crystallography.
Only 32 possibilities exist and these are the 32 crystal classes that are grouped into 6 crystal systems.
These are specific to the various crystal systems, intersecting at given angles and being of given lengths specific to each crystal system.
www.minsocam.org /MSA/K12/crystals/xlsystems.html   (139 words)

  
 How To Identify Minerals: Crystal Form
The axes of the crystal, the angles at which the axes intersect, and the degree of symmetry define each system.
Crystals are usually shaped like blocks, with similar and symmetrical faces.
The crystal has three axes of symmetry, all at right angles to each other, and all of the same length.
www.sdnhm.org /kids/minerals/howto-form.html   (227 words)

  
 Crystal grower spec for crystal grower applications with Czochralski crystal grower system
The induction load coil will be designed and sized for a 2 1/2" OD x 2 1/2" high crucible with 3/4” allowance on the inside diameter of the coil for suitable ceramic insulation.
System controls are contained in a 19" rack that also contains a control power transformer and the manual puller motor controls.
The system will be fully assembled and tested at Thermal Technology Inc., Santa Rosa, California.
www.thermaltechnologyinc.com /products/7004_CI_Spec.htm   (476 words)

  
 Reference.com/Encyclopedia/Orthorhombic crystal system
In crystallography, the orthorhombic crystal system is one of the 7 lattice point groups.
Orthorhombic lattices result from stretching a cubic lattice along two of its lattice vectors by two different factors, resulting in a rectangular prism with a rectangular base (a by b, which is different from a) and height (c, which is different from a and b).
The point groups (or crystal classes) that fall under this crystal system are listed below, followed by their representations in International {Hermann-Mauguin) notation and Schoenflies notation, and mineral examples.
www.reference.com /browse/wiki/Orthorhombic   (170 words)

  
 Crystal Forms | Crystal System
A Pinacoid is composed of only two parallel faces, forming tabular crystals such as Ruby.
A Hexagonal (Trigonal) Prism is comprised of of two hexagonal bases connected by a set of six rectangular faces that run parallel to, and never converge with an axes in the crystal.
There are several crystal forms in the Cubic crystal system that are common in Diamonds, Garnet, Spinel and other symmetrical gemstones.
www.khulsey.com /jewelry/crystal_forms.html   (586 words)

  
 Crystal View
Both the new Crystal View 2² two-piece projection system and the award-winning Madrigal Imaging MP-D1 D-ILA projector will be on display at the Earthquake Audio booth (# 20084D), located in the Las Vegas Convention Center.
Crystal View was formed in June 2002 by Gary Guidi, President of HI-Rez Projections -- a company that has been specializing in CRT projector service and remanufacturing since 1992, and David Wolff, former General Manager of Vidikron of America -- a company that sold high-quality CRT and single lens projectors.
Crystal View presently markets the Crystal View 1, 9-inch CRT projector; Crystal View 2 and 3, 8-inch CRT projectors; Madrigal Imaging MP-9, 9-inch CRT projector; Madrigal Imaging MP-8 8-inch CRT projector; and Madrigal Imaging MP-D1 D-ILA projector.
www.crystalviewinc.com /pressrelease_2piece.htm   (479 words)

  
 Crystal Ball 7.2.2 System Requirements
Crystal Ball 7.2.2 is the most recent version of Crystal Ball.
Crystal Ball 7.2.2 is an application built against and tested on Microsoft.NET Framework 1.1 (with.NET Framework 1.1 Service Pack 1) and will run by default on.NET Framework 1.1 on a machine containing.NET Framework 1.1 as well as other versions of the.NET Framework (for example, 1.0 and/or 2.0).
Crystal Ball 7.3, targeted for the first quarter of 2007, will be officially supported on Microsoft Office 2007.
www.crystalball.com /support/installation/cb7readme.html   (858 words)

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