Ice as a Mineral
A Stefanie Hubbard Production
for GO336 Mineralogy
Created in conjunction with Old Mother Hubbard Creations



Introduction    Ice Facts    Snowflake Images    Links and References

Introduction


 
A giant slab of translucent glacial ice,
up to 100 feet tall, slips into a crevasse
at the toe of a glacier. Image taken from:
http://www.airbornescientific.com/Glaciers.htm.
 Ice is everywhere.  It is in the sky in the form of snow, sleet, hail and crystal. Cubes and frost are forms of ice that can be found in our freezers. Ice is even in outerspace on other planets and in comets.  Most of the ice on Earth is in the form of glaciers. But why is ice considered a mineral and water is not?  Ice meets the criteria of the definition for a mineral:  1) It is solid below zero degrees C, 2) It is homogenous, 3) natually occurring, 4) has a crystalline structure, 5) has a definite chemical composition, and 6) is formed by inorganic processess  (Hurlbut)

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Ice Facts

Ice is a mineral with the chemical formula H2O.  However it must be in a frozen state to qualify as a mineral (Hurlburt, 2).  The solid phase of water normally occurs at or below 32 ºF, 0 ºC, or 273 º K.  Ice belongs to the hexagonal crystal system with a crystal class of 6/m2/m2/m.  The space group is P63/mmc.  Ice has a hardness of 1½ and a specific gravity of 0.9167. It is brittle and has a conchoidal fracture.  In snow crystals the habit is stellate with six rays. On water, ice crystals may form as elongated and lath-like (Roberts, 295).  Ice's habit is from massive to granular.  It may be transparent and clear, white if it has inclusions of gas bubbles or flaws, or blue, blue-green in thick layers. Ice has a vitreous luster and colorless streak (Frye, 639).

There are numerous uses for ice, for our: drinks, coolers, injuries, and sculptures.  Ice plays a big part in recreation: ice skating, hockey, skiing, snow boarding, sledding, and ice fishing.  Before  refrigeration, ice was used to keep food from spoiling, and in some countries it is still used for this purpose.  Ice may be used for medical purposes, such as to lower a patient's body temperature for surgery without anesthetic. Ice crystals can be easily seen in a freezer, on frozen food, in the ice cube tray, or on the freezer walls as moisture accumulates forming ice crystals.  In nature ice crystals form over bodies of water when the water cools below the freezing point.  Ice crystals come from the sky as snow, freezing rain, sleet, hail, and frost (Roberts, 295). 

Large amounts of ice are found in glaciers formed from compacted and recrystallized snow.  There are also semi-permanent areas of snow and permafrost at higher latitudes (Frye, 639). Although ice may not commonly be thought of as a mineral it meets the criteria of the definition for a mineral.  It is solid below 0 ºC, homogeneous, naturally occurring, crystalline structure, has definite chemical compostition of H2O, and is formed by inorganic processes (Hurlbut pg 1).

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Snowflake Images

       
 These images are taken from the Jericho Historical Society, http://www.snowflakebentley.com, taken by William Bentley.  Notice the hexgonal symmetry of the snow crystals.  No two snowflakes are alike. 

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Links and References

This page was created on 9 December, 1999. Send me e-mail to: hubbards@esuvm.emporia.edu
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