Subject: Why does volcanic ash look like ash from things that were once alive?

My sixth grade class has been studying volcanoes.  We were examining some 
authentic volcano ash and found some interesting similarities to the ash 
that can be found in any fireplace or barbeque?  The comparison of non-
living material versus living material that has been burned to ashes has 
raised some curiosity in my students.  Are the two types of ashes the same, 
or are they totally different?  Are there some similarities besides both are 
the byproduct of used fuel?

Re: Why does volcanic ash look like ash from things that were once alive?