The Oxides

Among important examples are Magnetite (Fe3O4) and Maghemite (Fe2O3), which are magnetic. Magnetite is commonly called lodestone and can be permanently magnetized. Large deposits segregate from igneous magmas at high temperatures and are mined near the surface as iron ores. Other forms of iron oxides are hematite (another form of Fe2O3), goethite (pronounced GHER-tite HFeO2) and limonite (FeO[OH].nH2O). These are oxidized iron minerals, cousins of ordinary rust.

How do oxides relate to the magma chamber?
Oxides are common in geochemical environments poor in silica. Silicates form easily, so if silica is used up then the oxides will remain to be formed.

The structure is complex; octahedral and dodecahedral crystals, very stable against weathering but dissolves slowly in HCl- (hydrocloric acid), see dissolution.


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The Oxides

Among important examples are Magnetite (Fe3O4) and Maghemite (Fe2O3), which are magnetic. Magnetite is commonly called lodestone and can be permanently magnetized. Large deposits segregate from igneous magmas at high temperatures and are mined near the surface as iron ores. Other forms of iron oxides are hematite, goethite (pronounced GHER-tite) and limonite. These are oxidized iron minerals, cousins of ordinary rust.

How do oxides relate to the magma chamber?
Oxides are common in environments poor in silica. Silicates form easily, so if silica is used up within the magma chamber, then the oxides will be formed.

The structure is complex; octahedral and dodecahedral crystals, very stable against weathering but dissolves slowly inhydrocloric acid, see chemical weathering.


This is a view of the Earth.
Click on image for full size version (40K GIF)
Image from: NOAA

Go to a listing of Rocks by mineral group


The major types of minerals

Not applicable at this reading level.


This is a view of the Earth.
Click on image for full size version (40K GIF)
Image from: NOAA

Go to a listing of Rocks by mineral group



Last modified November 15, 1997 by the Windows Team

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