Black & white film about exploding rocks

[Dennis]

I've been trying remember the title of this film. It's about a group of scientists who discover an unknown type of mineral in the waters of an underground lake. One of the properties of this rock is that when dried out it explodes very violently, sort of a nuclear bomb the size of a golf ball. A catastrophe, natural or man made, is about to uncover and dry out a vein of this stuff big enough to destroy the earth. I seem to recall that the solution to this involved blowing up Hoover dam or something similar. I do know this is not "The Monolith Monsters", the black rocks don't grow, they just explode. The film is from the 50's, at least it has that kind of feel to it.

[Andrew]

The Night the World Exploded!

Dave has a review over at Scifilm.org:

http://www.scifilm.org/musing1105.html

[RCMerchant]

The Night the World Exploded!

Dave has a review over at Scifilm.org:

http://www.scifilm.org/musing1105.html

Dammit! I just found it in my copy of SCIENCE FICTION MOVIES !!! Ya beat me to the punch! 

[Dennis]

Gentlemen we have a winner, it is "The Night the World Exploded". This has been driving me crazy off and on for the last couple of weeks. Andrew, RC, you guys may have preserved my sanity, such as it is, thank you.