Subject: Is it safe to keep volcanic rocks/materials in one's posssession?

I have a number of volcanic materials, but I read recently that volcanic ash is 
radioactive and can be used to determine the age of past eruptions.  I've also 
read that volcanoes are powered by radioactive activity and that radioactive 
rocks can be spewed out during eruptions.  Does this mean that I should be 
concerned?  I have a number of rocks, ashes and lahars and also some kind of 
sculpture that was fashioned, I believe, from a "holey" volcanic material that 
might be ash/cement or some other material.  It is brittle and crumbles fairly 
easily.

Thank you for your help.

Re: Is it safe to keep volcanic rocks/materials in one's posssession?