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Dry Ice; Mineral?
Name: Michael
Status: other
Grade: 12+
Location: SC
Country: USA
Date: N/A
Question:
Is carbon dioxide in it's frozen form(dry ice)
a mineral? And if it's not is it because it lacks a
crystalline structure?
Replies:
Michael,
I do not think it could be accurate to describe Dry Ice
as a mineral as it fails to meet the definition.
Any of a class of substances occurring in nature,
usually comprising inorganic substances, as quartz or
feldspar, of definite chemical composition and usually of
definite crystal structure, but sometimes also including
rocks formed by these substances as well as certain natural
products of organic origin, as asphalt or coal.
Dry Ice is solidified carbon dioxide, which does not occur in
Nature - at least not in the Earth's crust. On Earth CO2 only
occurs as a gas, mostly in the atmosphere but it is also expelled
from volcanoes and occurs as inclusions in some rock forms,
including pumice where it fills some of the vesicles (bubbles)
in the rock.
Now if you were to allow your definition to include planets outside
Earth (where does Nature extend??) then you would have to allow
Dry Ice to be a mineral on Mars.
Nigel Skelton
Tennant Creek - Australia
Minerals have: fixed composition, crystalline structure and are
naturally occurring. Dry ice does not exist naturally on earth
so it is no, strictly speaking, a mineral. But who knows what we
will do when we find it naturally occurring on some moons of the
outer planets of our solar system. A very interesting question.
Dry ice from Titan would make an interesting addition to a mineral
collection, would it not?
R. W. "Bob" Avakian
Instructor
Oklahoma State Univ. Inst. of Technology
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Update: June 2012
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