Dennis,

You're probably right that it is obsidian. The cut face is just the unpolished saw cut but
it doesn't seem to have much luster even when wet. It's distinguishing characteristics are
the knobby surface and its weight (quite heavy for its size.) I found it in a pile of 2-4 inch
landscaping cobbles on the east mesa in Albuquerque, NM. The west mesa has several
small volcanoes which could be the source of the obsidian.

Thanks for your comment.

From Roy Johnson - August 22, 2010 at 20:25:18
Email: rjohnson410[ ]comcast.net

Message: 69326