Crystalline,Systems,2004,gggem education Crystalline Systems
Translation jobs are undertaken by professional translators who are well versed with at least two languages.Translation can work at two levels: inter-state or regional language translation and inter-national or foreign language translation. Some forms of parent involvement with the school such as communications with school, volunteering, attending school events and parent--parent connections appeared to have little effect on student achievement, especially in high school. Helpi
© 2004 gggems.com All rights reserved. 7 systems of crystallization: There are 32 possibilities of combinations of the elements of symmetry (axis of rotation, symmetry plane, centers combined inversion and operations). Since the discovery of the crystals reticular structure, one could show by calculation that to these 32 classes which relate to the shapes of the crystals, correspond 230 types of network. One immediately realizes the complexity of the reasoning which should be made to know all the possible combinations. The 32 classes are grouped in 7 systems. Here are the figures. CUBIC SYSTEM QUADRATIC SYSTEM HEXAGONAL SYSTEM Go to Garnet Go to Zircon Go to Apatite Diamond, garnet, spinell. Zircon Beryl, Apatite -------------------------------------------------- TRIGONAL SYSTEM ORTHOROMBIC SYSTEM MONOCLINIC SYSTEM (Subdivision of the hexagonal system) Go to Topaz Go to Orthoclase Go to Corundum Go to Tourmaline Calcite, corundum, tourmaline, quartz. Chrysoberyl, topaz Orthoclase ------------------------------------------------- TRICLINIC SYSTEM The symmetry of crystals : appear the following symmetrical operations: > > · Rotation· Inversion by symmetry plane· Inversion by a center· Combination of rotation and inversion The crystals show in their form and their structure of the properties of characteristic symmetry. And like there is a cor - respondence between reticular plans and faces of the crystals, there is a fundamental correspondence between internal symmetry and external symmetry. We imagine the drawing of a tapestry, it will repeat ourselves by a simple parallel displacement (translation). When a crystal is examined, the first All the geometrical operations which point which draws the attention is a cause a repetition of the pattern are certain symmetry. One can see the called operations of symmetry. In the repetition of faces identical to various shape of the crystals (external format), places of the crystal. These repetitions this translation does not appear directly. are controls by laws of symmetry, On the other hand, in their morphology, Albite the way in which they are repeated is determined by operators of symmetry, there are three principal types of them: Axis of symmetry, symmetry plane and the center of symmetry. GGGEMS.COM ¦Gemology ¦ Corundums ¦ Tourmaline Characteristics ¦ Garnets ¦ Cutting Styles
Crystalline,Systems,2004,gggem