[Rockhounds] Re. Fulgurites

[Alan Goldstein]

I get some from a friend in Australia occasionally. They are small hollow tubes. The last one he send was poorly wrapped and broken. They are pretty fragile.

Alan

----- Original Message -----
From: Mark Stanley <markstanley at bellnet.ca>
Date: Monday, September 15, 2008 14:30
Subject: [Rockhounds] Re. Fulgurites
To: Rockhounds at lists.drizzle.com

> I have collected Fulgurites for a few years now.  
> Personally finding them is very difficult if not impossible in 
> the area that I live.  The best indicator is burned 
> vegetation and melted and disturbed soil.  The problem is 
> that after a few weeks the vegetation has regrown and covered 
> the ground again hiding any evidence of the melt. 
> 
> I have had better luck by work of mouth, and information from 
> other collectors.
> 
> There appears to be a better chance of a Fulgurite being created 
> when the lightning directly strikes the ground.  I expect 
> that if it hits a tree, utility pole or building it looses 
> energy that is needed to make the melt.  One thing I have 
> seen is that there are few things that are typical about 
> lightning.  It is very unpredictable.
> 
> There are some differences between true Fulgurites that have 
> been created by lightning and those that result from downed 
> hydro lines (hydro melts).  With lightning, the energy is 
> in hundreds and thousands of kilovolts, downed hydro lines are 
> in thousands of volts.    They can look very 
> similar, but if you examine the glass as polished thin sections, 
> the lightning melts show a far greater level of melt of the host 
> soil or sand.  Hydro melts typically will still have 
> fragments of some of the original silicates mixed in the 
> glass.  All are melted soil and rock, but they should be 
> represented as lightning created or man induced.
> 
> Check out the following:  http://www.turnstone.ca/fulgur.htm
> http://www.turnstone.ca/silicide.htm
> 
> The largest hydro melt that I have excavated was about 3 metres 
> in length, it was from a 3000 volt line that discharged through 
> a residential TV tower for about 3 hours.  I had to wait a 
> couple of days for it to cool enough to dig.  While its 
> size was similar to lightning fulgurites, it was a mass of 
> hundreds of small branches coming off of the main mass.  
> True Fulgurites typically are a single large branch, or several 
> large branches, that tapers down in size and have only a few 
> small branches exiting off.
> 
> The Fulgurites from the Sahara Desert that are offered on Ebay 
> and at shows are quite often 1 to 20 cm long and less than 2 cm 
> in diameter.  I  have a number of examples from all 
> over North America that range in length from 10 to 60 cm and 
> have diameters of 3 to 22 cm. Some have come from Ebay, some 
> from shows and a very few have been self collected.  The 
> question I have is why are those from the Sahara Desert area so 
> much smaller? 
> 
> 
> Mark Stanley
> Norwood, Ontario, Canada
> 
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