Pyrite Fluorite Carrollite,

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://library.thinkquest.org/C005277/Crystal.html

http://www.windows2universe.org/earth/geology/crystal_shapes2.html

http://www.mindat.org/photo-347085.html


Pyrite

Crystals with cubic (Isometric) structures

Fluorite


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.thenaturalsapphirecompany.com/education/related-information/trigonal-crystals/







Quartz


Magensite


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


http://www.yourgemologist.com/crystalsystems.html

Crystals with tetragonal structures

http://www.mineraltown.com/reports/7/7.php?idioma=2


Stolzite Chantalite, Grossular


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





Samuelsonite


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





Adamite


Columbite (Mn)


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





Milarite


Nasonite


Hibonite

Crystals with hexagonal structures







Triclinic crystals

Least symmetrical – no equal sides or angles

can be very strangely shaped





Paradamite


Yvonite


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

http://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



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


http://www.mindat.org/crystalsystems.php




http://www.kidzworld.com/article/1587-all-about-snowflakes


http://www.ducksters.com/science/crystals.php



Documents

Pyrite Fluorite Carrollite,