[Rockhounds] when volcanoes drop bombs: giant crystal payload

[DonH]

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