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+ Mineralogy
+ Geology
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Al Grayson

Why are quartz considered silicates, but not oxides?

Andrew James  Follow

Quartz is one of those "either or" minerals. While it is synthetically an oxide of silicon, it is additionally crystallographically a silicate - it's structure is the system structure of the Tectosilicate superclass. Prior mineralogical works and chemistry works (old and new) regarded it as an oxide.

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BJ Chippindale  Follow

Quartz can be considered as an oxide of silicon or as a silicate. I refer you to this discussion: General : Today's debate

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Andy White  Follow

Quartz is a natural crystal of silicon dioxide it is a molecular lattice compound. Silicates are salts or esters of silicic acid they have additional elements in their structure and are ionic or molecular in the case of the esters.

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Carl Miller  Follow

Quarz:

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Danny Beckett  Follow

Quartz is a specific mineral. Silica is an ill-defined term for a composition (SiO2). Quartz is made of silica. So is chalcedony. So is cristobalite. So is tridymite. So is agate. So is amethyst. Sometimes, speaking of hydrothermal alteration, we say a rock is “flooded with silica.” That usually means we don’t know what mineral of silica composition is present. Olivine is made of silica and magnesia.

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