[Rockhounds] Quartz Sphere results

[The Hammer]

I want to thank everyone for your awesome feedback in helping me.
The short version is, I do believe that the sphere is quartz.

Test results:
Hardness: Quartz not glass
Density: Quartz or Glass
Fractures: Quartz not glass
Ultraviolet Light (this test was cool): Quartz not Glass

A picture of the sphere can be found here:
http://farm4.static.flickr.com/3025/2892357127_fa71da56b7_b.jpg

The longer full version of the story from my personal blog is below:

A short while ago, I purchased a sphere at a yard sale. I could tell by
its feel that it was not plastic, and was most likely either quartz
(rock crystal) or glass. I sent out a message to some of the mail lists
that I belong to, hoping that someone would have some quick and easy
suggestions to accurately determine whether the sphere was quartz or
glass. They quickly responded with ways to differentiate between the
two.

I decide to experiment today to find my answer. It's
pouring heavy rain out there. I grab a jacket, the sphere and a few
notes. I head out to the "workshop". First thing I do is take off the
wet jacket, and hang it to dry. Let the testing begin.

Hardness.
Sounds pretty simple. A steel file should scratch glass, but not
quartz. If I can only find a file. I search for about five minutes and
finally find one. It doesn't seem to make a scratch, so I'd like to say
it is quartz. Just the same, I'll feel better doing a bit more.

Density.
Not a definitive test, but figured it was a good starting point. The
specific gravity of quartz is about 2.65. Glass can vary, I'm told,
from about 2.4 to 2.8. The other factor is I may not have an extremely
accurate measurement here either, so if the answer shows close to
quartz, it may not be a definite proof. But I'd guess a high or low
density would dismiss the sphere as glass. I need my ruler to measured
the diameter. Another trip in the rain and back. I need a calculator.
Okay, the diameter seems to be about 4.3 cm, perhaps a tad less. The
mass came to 106.4 grams. I need a calculator another trip in the rain
and back. The density came to about 2.6. I felt my accuracy range
allowed me to say it might be quartz and continue.

Inclusions
and fractures. I'm told that glass would have no visible inclusions or
fractures, or perhaps round bubble. Quartz could have inclusions and
fractures in straighter or more jagged shapes. I decide to use my
loupe, but it is nowhere to be found in the workshop. Yet another trip
into the rain that got even heavier and back again. The sphere did
indeed have some of these fractures. So now I'm reasonably sure it is
quartz. I decide to do one last test, to make a definitive decision, in
case.

Ultraviolet light. Short wave ultraviolet light will
travel through quartz, but not through glass. I had to get a ladder to
climb up high and unplug my ceiling lights, something I didn't feel
like doing after my three trips out in the rain. I did it any way, and
found this experiment to be a lot of fun and rather fascinating. I
brought out a piece of scheelite that glows a bright blue, but only
under short wave ultraviolet light. I shine my UV lamp on it. Hello
there all happy and bright. I take a piece of glass closest to the size
and shape of the sphere that I can find. The stone no longer glows,
only appearing its normal gray since the class filters those short wave
rays. I then take the sphere and move it eclipsing the UV lamp, as the
glas did. The scheelite glow its bright blue.

So I feel that I can say that the sphere is quartz.  Yay!

I
also took a sphere that I bought several years ago, and ran it over the
UV lamp with the same results. I'm really happy with my results, even
though I do see that I need to be more organized. But for now, I just
need to wait for my jacket to dry out!

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