Help request for identifying "ruby"

Hi all...

I was wondering if anyone could help me with techniques to determine
what a "gemstone" actually is.

I bought a "lab created simulated ruby" via eBay recently, which I had
presumed based on my cursory web search readings to be synthetic ruby,
a.k.a. corundum, a.k.a. Al2O3.

I've found based on web searching that the industry terminology seems
to be all over the place regarding the meanings of terms such as
"created", "lab", "synthetic", "simulated" and the like. What little
consistency I could find indicated that "synthetic" indicated a gem
that was created artificially, but of the same material as the "real"
gem, therefore having nearly identical physical characteristics, while
"simulated" indicates the gem is created from an entirely different
substance that has some similarity in appearance to the "real" gem.

Further reading suggests this "ruby" may be actually be synthetic
"spinel".

Since the vendor doesn't seem to be in a great hurry to answer my
e-mail inquiries, I'm turning to Usenet. I'm not concerned about this
from a value/purchase perspective, since I got an interesting, pretty
25mm *something* for only about $20 (which has paid me back already in
terms of the interesting reading on gem materials and manufacturing
methods I've already done), but a big part of wanting this was as a
conversation piece, and it's hard to have a conversation about
something when you have no idea what it is.

Any ideas/pointers out there? Some non-destructive test(s) to narrow
it down, maybe?

Thanks much,

--Randy

Randall Long wrote:
=

Hi all...
=

I was wondering if anyone could help me with techniques to determine
what a "gemstone" actually is.
=

I bought a "lab created simulated ruby" via eBay recently, which I had
presumed based on my cursory web search readings to be synthetic ruby,
a.k.a. corundum, a.k.a. Al2O3.
=

I've found based on web searching that the industry terminology seems
to be all over the place regarding the meanings of terms such as
"created", "lab", "synthetic", "simulated" and the like. What little
consistency I could find indicated that "synthetic" indicated a gem
that was created artificially, but of the same material as the "real"
gem, therefore having nearly identical physical characteristics, while
"simulated" indicates the gem is created from an entirely different
substance that has some similarity in appearance to the "real" gem.
=

Further reading suggests this "ruby" may be actually be synthetic
"spinel".

It would be quite easy to determine if what you have is a synthetic spine=
l or a
synthetic ruby. If you have the right equipment. =


Go to a jewelry store that has a gem testing lab, and ask them to put the=
stone
on their refractometer first. The two stones have different refractive i=
ndeces,
i.e. synthetic ruby 1.762 - 1.770 and synthetic spinel 1.73, =B1 .01

Note that Synthetic Ruby is "double refractive", synthetic spinel is not.=


The absorption and emission spectra are also quite different.

Second, the specific gravity can be tested, which is also quite different=
in the
two stones. Synthetic as well as real Corundum 4.00 (+ or minus .03), Sy=
nthetic
Spinel 3.65 (- .12, + .02)

Finally the hardness is different. Synthetic Ruby is 9, Synthetic Spinel=
is 8

A gem dealer, could most likely determine what you have with just a 10 po=
wer
loupe.

Abrasha
http://www.abrasha.com

Randy,
The easiest physical test, and very conclusive, is to determin the
specific gravity .
Corundum SG = 4.0
Spinel SG = 3.6
With a 25 mm. stone, you shold be able to identify your stone.
Ask someone in a physics or chemistry lab ( school ) to weigh it in
Air, then imersed in water.
Your book , any midschool science book wiill give you the formula.
I would, except I have a persistant old cat laying on my arms now.
ROBB

(Randall Long) wrote
I was wondering if anyone could help me with techniques to determine
what a "gemstone" actually is.

I bought a "lab created simulated ruby" via eBay recently, which I had
presumed based on my cursory web search readings to be synthetic ruby,
a.k.a. corundum, a.k.a. Al2O3.

Further reading suggests this "ruby" may be actually be synthetic
"spinel".


Any ideas/pointers out there? Some non-destructive test(s) to narrow
it down, maybe?

Thanks much,

--Randy

Hi Randy,

I bought a "lab created simulated ruby" via eBay recently, which I had
presumed based on my cursory web search readings to be synthetic ruby,
a.k.a. corundum, a.k.a. Al2O3.

The operative words here are synthetic & simulated.

Simulated means "looks like". It can be anything at all as long as it
sort of looks like the thing it's simulating. In this case all it
needs is a red color.

Synthetic on the other hand means 'identical to the real thing, but
man made'.

In your case it was a man made red stone. It could be glass or most
anything else that's red. It couldn't be a synthetic corundum, because
it was a 'simulant'.

Dave