[Rockhounds] quartz sphere question

[Axel Emmermann]

I have dome "herkimer quartz" from Afghanistan. 
The gas bubbles inside contain a naturally cracked petroleum with methane
bubbles, petroleum and asphalt. All very nicely fluorescent too.
The bubbles sometimes show a "negative" quartz crystal shape. As if a small
quartz crystal inside dissolved somehow. Rather puzzling. 

Axel

> -----Oorspronkelijk bericht-----
> Van: rockhounds-bounces at lists.drizzle.com
[mailto:rockhounds-bounces at lists.drizzle.com]
> Namens Pmodreski at aol.com
> Verzonden: vrijdag 26 september 2008 4:29
> Aan: rockhounds at lists.drizzle.com
> Onderwerp: Re: [Rockhounds] quartz sphere question
> 
> I'll try too...
> 
> Almost all quartz crystal will have some imperfections--fractures or
cloudy
> patches or inclusions.  If it does have them (check it out with a
magnifying
> lens), it's probably confirmed as quartz.  If it has none, if it  is
> absolutely clear with no flaws at all, it is likely glass.
> 
> Along the same line, to be more sure; scrutinize any such imperfections
> closely.  If they are bubbles, little spherical ones, it is probably
glass.  If
> they are lines or planes of some sort, then, quartz.   If you don't see
ANY
> such things of any sort--well, as I said, I'd suspect  glass, but one
couldn't be
> absolutely certain.
> 
> Look at in under a black light too.  A lot of glass fluoresces, at  least
> slightly; most quartz does not, except for any inclusion particles
perhaps.
> 
> Measuring the specific gravity is probably "easier said than done".   One
> easy way; weigh it on an accurate balance, then measure the diameter with
an
> accurate pair of calipers, and calculate the volume and then the specific
> gravity, using "simple geometry which everyone remembers (ha ha) from high
school &
> college math & physics.  Quartz should be very close to  2.65 grams per
cubic
> centimter; glass, as Kreigh says, should be somewhat  less.
> 
> P.S., I just tried looking this up (density of glass), and the two are so
> close, it would not be very reliable to use density to distinguish them,
I'm
> afraid.  I find the density of common "crown" glass to be around 2.5 g/cc,
but
> can vary from 2.4 to 2.8, and "flint glass" and lead crystal (which is
glass)
> are even higher.  Oh well.
> 
> cheers,
> Pete
> 
> 
> 
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