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

Hi Rob,

Thanks for your question, and I'm glad you're taking precautions to keep 
yourself safe.

In almost every case, volcanic material is safe enough for you to handle.  
However, some volcanoes (one is in Antarctica) have produced lava 
containing radioactive materials.  The best way to be sure would be to 
take the samples to be scanned with a geiger counter (Check your local 
university chemistry/physics department) which will undeniably tell you if 
your samples are radioactive.  However, it is very unlikely that your 
samples are hazardous.

Cool stuff:
* The fine powder that Volcanoes spew out is called "Tephra", so any 
newscaster or Mad Scientist that uses the term, "Volcanic Ash" is not 
quite on the mark.  "Ash" is the residue left over after combustion, and 
Volcanoes are not actually combusting.
* To determine the date of a volcano's past eruption, Geologists will 
radiocarbon date any organic material above and below the Tephra layer.  
Carbon-14 dating is only good up to 60,000 years ago.  Any older than 
that, and there's no C-14 left to test.  (Speaking of Radiation, you have 
a small amount of radioactive Carbon-14 in your body right now, but it's 
not enough to cause you any health problems.)  To test the age of the 
rocks themselves, Geologists use Argon-Argon dating, which is good for 
millions and millions of years. 


Cool Links:
Science Explained -
 The Montserrat Volcano

USGS - Volcano Hazards

Volcano World

Radiocarbon Dating WEBinfo

Volcanic/Glacier Radiocarbon Dating