Yin Xuan Lao's Blog

May I Ask?

17th Aug 2008

Excuse me... I knew there's a red obsidian but how does it differ from the black one? Is the composition different? Or the formation? Anybody whose kind enough to help me may reply... :( <

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Comments

The difference between red and black in obsidian is the oxidation state of the iron in the glass. Red is due to inclusions of hematite while black is due to magnetite.

http://volcanoes.usgs.gov/Products/Pglossary/obsidian.html
http://canmin.geoscienceworld.org/cgi/content/full/45/3/551

David Von Bargen
18th Aug 2008 7:51pm

You know about that "iron" thing right? The red obsidian may have traces of iron that's why it looks red. It is just because the ones containing magnetite that makes them appear black are simply more common (I think).
By the way, will ya please visit my page? : >

Stephen Joseph Lao
31st Aug 2008 2:20am

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