Post on 18-Jan-2016
transcript
Crystals
The 7 different types of Crystals
Cubic (Isometric) Crystals Not always shaped like a cube Isometric – three sides with the same
length, height and breadth Can be shaped like a octahedron (8 sides)
or dodecahedron (12 sides) Salt is an example of a cubic crystal found
in natural crystals
ThinkQuest, 2013http://library.thinkquest.org/C005277/Crystal.html
Gardiner, 2007http://www.windows2universe.org/earth/geology/crystal_shapes2.html
http://www.mindat.org/photo-347085.html
http://www.mindat.org/photo-200876.html
Pyrite
Crystals with cubic (Isometric) structures
Fluorite
http://www.mindat.org/photo-364349.html
Carrollite, Calcite
Trigonal Crystals
Four axes, with three that are equal in length and one that is longer/shorter
Similar to hexagonal crystals due to its physical shape, except trigonal structure is less defined
Quartz is one of the most common forms of trigonal crystals
The Natural Saphire Company, 2013 http://www.thenaturalsapphirecompany.com/education/related-information/trigonal-crystals/
ThinkQuest, 2013http://library.thinkquest.org/C005277/Crystal.html
http://www.mindat.org/photo-456858.html
Quartz
http://www.mindat.org/photo-87813.html
Magensite
http://www.mindat.org/photo-279048.html
Ikranite
Examples of crystals with trigonal structure
Tetragonal Crystals
When looking through a microscope there structure is very similar in shape to cubic crystals except they are longer in length
look like prisms and double-pyramids
Gardiner, 2007http://www.windows2universe.org/earth/geology/crystal_shapes2.html James, 2011http://www.yourgemologist.com/crystalsystems.html
Crystals with tetragonal structures
http://www.mineraltown.com/reports/7/7.php?idioma=2
http://www.mindat.org/photo-38543.html
Stolzite Chantalite, Grossular
http://www.mindat.org/photo-488253.html
Sphalerite
Monoclinic Crystals Also form as prism shapes or double
pyramids They appear to have been titled which
makes them look different to cubic and tetragonal crystals
Most common crystal structure One of the least symmetrical structures
Gardiner, 2007http://www.windows2universe.org/earth/geology/crystal_shapes2.html James, 2011http://www.yourgemologist.com/crystalsystems.html
http://www.mindat.org/photo-449174.html
Samuelsonite
http://www.mindat.org/photo-94165.html
Spurritehttp://www.mindat.org/photo-173157.html
Crystals with monoclinic structures
Orthorhombic crystals
Also appear like double-pyramids (two stuck together)
Looks like tetragonal crystals, although the centre where the pyramids join is not a square
Gardiner, 2007http://www.windows2universe.org/earth/geology/crystal_shapes2.html James, 2011http://www.yourgemologist.com/crystalsystems.html
http://www.mindat.org/photo-20752.html
Adamite
http://www.mindat.org/photo-6832.html
Columbite (Mn)
http://www.mindat.org/photo-500205.html
Walkerite
Crystals with orthorhombic structures
Hexagonal crystals
Six-sided - Looks like the hexagon shape, only in prism form
Sides may not always be even, but the crystal will still have six
Gardiner, 2007http://www.windows2universe.org/earth/geology/crystal_shapes2.html James, 2011http://www.yourgemologist.com/crystalsystems.html
http://www.mindat.org/photo-477006.html
Milarite
http://www.mindat.org/photo-58813.html
Nasonite
http://www.mindat.org/photo-169922.html
Hibonite
Crystals with hexagonal structures
Triclinic crystals
Least symmetrical – no equal sides or angles
can be very strangely shaped
Gardiner, 2007http://www.windows2universe.org/earth/geology/crystal_shapes2.html James, 2011http://www.yourgemologist.com/crystalsystems.html
http://www.mindat.org/photo-478061.html
Paradamite
http://www.mindat.org/photo-42400.html
Yvonite
http://www.mindat.org/photo-306825.html
Gormanite
Crystals with triclinic structures
Crystals according to their physical/ chemical properties
Covalent Crystals All the atoms share the electrons that form a
bond to create a solid shape “One big molecule” High melting pointMetallic Crystals Individual metal atoms Outer atoms flow freely around the structure/
shape High melting point
Campbell, 1998-2011http://www.chemistry.co.nz/crystal_types.htm
Ionic Crystals No covalent (shared) bonds between
atoms Atoms held together by slow-moving
force Often have a hard structure, high
melting point Molecular Crystals Structure is soft, low melting point recognizable molecules that are held
together by hydrogen bonds Sugar is a type of molecular crystalCampbell, 1998-2011
http://www.chemistry.co.nz/crystal_types.htm
Snowflakes Are an interesting form of crystal, known as Ice
Crystals Formed when water freezes up in the clouds No two snowflakes are ever the same – each
have their own beautiful and unique structure Temperature has a big influence on the shape
the snowflake will be, and since temperature is always changing, different snowflakes are always created
So tiny it is only possible to see their complete structure under a microscope
(Kidzworld, 2013; Maki, 1993; Science for Kids, 2013).
http://www.its.caltech.edu/~atomic/snowcrystals/photos/photos.htm
Examples of Snowflakes
References
Campbell, HA. (1998-2011). What types of Crystals are there? Kiwi Web: Australia and New Zealand. Retrieved 22 October, 2013, from http://www.chemistry.co.nz/crystal_types.htm
Chao, I. and Ralph, J. (1993-2013). Minerals by Crystal Systems. Mindat.org. retrieved 22 October, 2013, from http://www.mindat.org/crystalsystems.php
Gardiner, L. (2007). Shapes of Mineral Crystals. Windows 2 Universe. Retrieved 22 October, 2013, from http://www.windows2universe.org/earth/geology/crystal_shapes2.html
James, R. (2011). The Seven Crystal Systems. Your Gemologist. Retrieved 22 October, 2013, from http://www.yourgemologist.com/crystalsystems.html
Kidzworld. (2013). All about Snowflakes. Retrieved 21 October, 2013, from http://www.kidzworld.com/article/1587-all-about-snowflakes
Libbrecht, K. G. (1999). Snow Crystal photo gallery. Snow Crystals.com. Retrieved 24 October, 2013, from http://www.its.caltech.edu/~atomic/snowcrystals/photos/photos.htm
Maki, C. (1993). Snowflakes, Sugar, and Salt. Crystals up close. Learner Publications Company: Minneapolis.
Science For Kids. (2013). Crystals. Ducksters. Technological Solutions. Retrieved 21 October, 2013, from http://www.ducksters.com/science/crystals.php
The Natural Saphire Company. (2013). Trigonal Crystals. Retrieved 22 October, 2013, from http://www.thenaturalsapphirecompany.com/education/related-information/trigonal-crystals/
ThinkQuest. (2013). Crystal Systems. Cubic Crystals. Retrieved 22 October, 2013, from http://library.thinkquest.org/C005277/Crystal.html