Siyuan Yue'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... :( <

Return to Siyuan Yue's Blog Index

Blog has been viewed at least 1068 times.

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

In order to leave comments to this blog post, you must be registered

Mineral

and/or Locality

www.mindat.org

Web

Copyright © Jolyon Ralph and Ida Chau 1993-2009. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them.Further information contact the Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of hundreds of members and supporters. If you would like to add information to improve the quality of our database, then click here to register. Current server date and time: 10th Nov 2009 12:46:48