obsidian

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obsidian

obsidian , a volcanic glass , homogeneous in texture and having a low water content, with a vitreous luster and a conchoidal fracture. The color is commonly black, but may be some shade of red or brown, and cut sections sometimes appear to be green. Like other volcanic glasses, obsidian is a lava that has cooled too quickly for the contained minerals to crystallize. In chemical composition it is rich in silica and similar to granite. It is favored by primitive peoples for knives, arrowheads, spearheads, and other weapons and tools.

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obsidian

A Dictionary of Earth Sciences | 1999 | | Â© A Dictionary of Earth Sciences 1999, originally published by Oxford University Press 1999. (Hide copyright information) Copyright

obsidian Volcanic glass of dacitic (see DACITE) or rhyolitic (see RHYOLITE) composition.

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AILSA ALLABY and MICHAEL ALLABY. "obsidian." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 12 Nov. 2009 <http://www.encyclopedia.com>.

AILSA ALLABY and MICHAEL ALLABY. "obsidian." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (November 12, 2009). http://www.encyclopedia.com/doc/1O13-obsidian.html

AILSA ALLABY and MICHAEL ALLABY. "obsidian." A Dictionary of Earth Sciences. 1999. Retrieved November 12, 2009 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-obsidian.html

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	Obsidian Re-Brands to Obsidian Strategics and Launches Washington D.C.-based Obsidian Federal. Business Wire; 11/8/2007
	Obsidian Finance Group and The Campbell Group Propose to Acquire Longview Fibre Company for $26.00 Per Share in Cash. Business Wire; 3/6/2006
	Obsidian Software Ranks 9th; Random Test Generator for Soft Cores. Business Wire; 9/20/2002

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	Obsidian Enterprises Delivers Improved Revised Proposal To Net Perceptions; Obsidian's Proposal Would Provide Net Perceptions Shareholders Opportunity to Elect to Receive Either $0.40 per Share in Cash or Two Shares of Obsidian Common Stock. PR Newswire; 12/8/2003; 700+ words ; Obsidian Enterprises, Inc. (BULLETIN BOARD: OBSD) , a holding company...oral and written communications, this is to again confirm that Obsidian Enterprises, Inc. ("Obsidian") is prepared to enter into a merger agreement with Net Perceptions...
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