[Rockhounds] when volcanoes drop bombs: giant crystal payload

[Axel Emmermann]

A step-cousin of my wife's step-mother-in-law (we tend to have complicated
family trees ;-))) spent a vacation on Vanuatu and slept one night on the
rim of a local and very active volcano crater.
During the night (while my wife's step-whatever was asleep in his tent) the
trade winds turned. Two weeks early apparently.
Suddenly our brave tourist (oh well, he's a volcanologist among other
things) was confronted with volcanic bombs flying his way.

One red hot bomb (head-size) landed 3 feet in front of him and broke in
half. He actually watched feldspar crystals of the size that you mention
grow. 
His main concern was to get on the other side of the rim before getting
killed so he marked the spot with a pile of rocks.
Next day the volcano was calmer and he retrieved one piece of the bomb. 

What people do to fill their display cabinets....

Axel



> -----Oorspronkelijk bericht-----
> Van: rockhounds-bounces at lists.drizzle.com 
> [mailto:rockhounds-bounces at lists.drizzle.com] Namens DonH
> Verzonden: woensdag 1 augustus 2007 6:31
> Aan: rockhounds at lists.drizzle.com
> Onderwerp: [Rockhounds] when volcanoes drop bombs: giant 
> crystal payload
> 
> 
> Howdy,
> 
> Today I was in the lab down the road at Washington State U. 
> and traded some of my specimens for someone's water-clear 
> feldspars.  He also had this, which he let me photograph.  It 
> is a volcanic bomb from near Spencer, Idaho.  The feldpsar 
> crystal inside it is 6 cm long!  It is also fluorescent a 
> dull, but saturated, deep red under SW UV.  I am going to 
> x-ray some of the smaller pieces tomorrow to find out what 
> flavor of feldspar it is.  Finding something like this is 
> much like spilling a small bowl of cake batter and finding a 
> perfectly baked cupcake inside it.  The photo lost a little 
> crispness when I converted from TIF to JPG but I think it 
> still conveys the wonder.
> 
> http://mysite.verizon.net/resqkdq4/feldsparbomblet.jpg
> 
> Another shot that shows the volcanic bomblet texture a little 
> better.  I was running around the hall looking for the best 
> window light to photograph while the lab manager was warming 
> up the mass spectrometer. 
> The crystal was perfect before the matrix broke open!
> 
> http://mysite.verizon.net/resqkdq4/bombletside.jpg
> 
> This is what I really do most of the time these days--fire a 
> high-powered laser to blast a path 0.03 millimeter wide and 
> 1.2 millimeter long into micro feldpsar crystals that are 
> from 0.5 to 1.5 millimeter long, in order to vaporize the 
> mineral and look for trace elements and isotopes.  Despite 
> the sound of it, this is the most dreary and tedious thing a 
> mineralogist can do, ever.
> 
> http://mysite.verizon.net/resqkdq4/laserfeldspar.jpg
> 
> 
> Good night,
> Don
> 
> 
> 
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