kunzite vs. morganite
Virginia Lyons
to say that not all the stones were well marked as to what they are.
I'm very embarrassed, but the kunzite and the morganite are really,
really similar in color. I would appreciate any suggestions on how I
can correctly identify which is moreganite and which is kunzite
without damaging the stones.
thanks
Virginia Lyons
vly...@best.com
John Miller
The best way is a simple check of refractive index, if you have a
refractometer. Both stones are doubly refractive. Kunzite will show an
R.I. of 1.660-1.676, and morganite 1.585-1.594.
If you don't have a refractometer, kunzite is likely to appear somewhat
more brilliant than morganite, due to the higher R.I., and generally is
highly dichroic, appearing almost colorless in one direction and rich
purplish-red to violet in another direction. Kunzite may also contain long
silk-like cavities.
As a general rule, it's a big mistake to try to identify stones by color
alone. Anyone who deals regularly in gemstones needs to acquire a
refractometer and learn how to use it, as it's often the quickest and
easiest aid to identification.
--
John Miller, Gemcutter/Graduate Gemologist/CNE
Gemology & Lapidary Pages - http://www.tradeshop.com/gems/
PeterWRowe
writes:
Another technique which might prove useful, especially if you have a large
number of stones to identify, and KNOW that that stones are either
Morganite or Kunzite, would be to use a specific gravity liquid between
the Morganite's S.G. of around 2.82, and the Kunzites considerably denser
3.18. The GIA S.G. liquid sets include one at 3.05 that would work just
fine, or you could get just a bottle of Methylene Iodide and some Benzyl
Benzoate to dilute it down to the required S.G. if you don't anticipate
needing the whole set in the future.. Then you could just dump in the
whole parcel at one time. The ones that float would be your Morganites,
while the Kunzites would sink. Aside from speed, this option is less
costly than the cost of a refractometer.
However, as John points out, the refractometer is pretty much a standard
indespensible tool for gem identifications, and if you are going to be
faced with such situations in the future, it would be well worth the money
to buy one. The refractometer gives you more information than a single
S.G liquid can, and the simple technique I mentioned above does have the
pitfalls of not necesarily alerting you if you happened to have something
other than those two gems in the parcel.
Hope this helps.
Peter Rowe
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Peter W. Rowe M.F.A., G.G.
Commercial and custom jeweler and metalsmith
Graduate Gemologist and Lapidary
Opinions expressed here are solely my own....... and subject to change
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John Miller
> Another technique which might prove useful, especially if you have a large
> number of stones to identify, and KNOW that that stones are either
> Morganite or Kunzite, would be to use a specific gravity liquid between
> the Morganite's S.G. of around 2.82, and the Kunzites considerably denser
> 3.18. The GIA S.G. liquid sets include one at 3.05 that would work just
> fine, or you could get just a bottle of Methylene Iodide and some Benzyl
> Benzoate to dilute it down to the required S.G. if you don't anticipate
> needing the whole set in the future.. Then you could just dump in the
> whole parcel at one time. The ones that float would be your Morganites,
> while the Kunzites would sink. Aside from speed, this option is less
> costly than the cost of a refractometer.
>
> However, as John points out, the refractometer is pretty much a standard
> indespensible tool for gem identifications, and if you are going to be
> faced with such situations in the future, it would be well worth the money
> to buy one. The refractometer gives you more information than a single
> S.G liquid can, and the simple technique I mentioned above does have the
> pitfalls of not necesarily alerting you if you happened to have something
> other than those two gems in the parcel.
Peter's suggestion about testing specific gravity is good, especially
if you're testing numerous stones as he mentioned, but there's one little
problem he barely touched but didn't elaborate on -- the S.G. of the test
liquids changes as the components evaporate, and from time to time you
have to add one or the other liquid to readjust the S.G., using a sample
stone of known S.G. to calibrate it. This is a bit of a nuisance. On
the other hand, the refractometer needs no such calibration. You just
need to keep the methylene iodide (the R.I. liquid) on hand and keep the
refractometer window clean and scratchfree.
David S. Geller
A woman wrote about the way to tell the difference between
Kunzite and Morganite:
> I just received a large parcel of colored gem stones, and I'm
sorry
> to say that not all the stones were well marked as to what
they are.
There is another way of telling two gems apart if you
only have a scale. Figure our what the stone would weight if you
could only MEASURE them. Using standard formulas, you could
figure the weight of an emerald cut gemstone this way (I chose
emerald cut, I don't know what shape her stones actually were).
Multiply Length X Width X Depth in millimeters. Then
multiply that answer times ".0020". Then multiply that answer
times it's specific gravity, which can be found in most gem or
jewelry books. The specific gravity for Morganite is 2.72 and for
Kunzite is 3.18. Here a sample of a stone that you know weighs
about carats and measures 10 x 8 x 3.5mm:
10 x 8 = 80, x 3.5 = 280, x .0020 = .56, then times the
specific gravity for Kunzite (3.18) = 1.78 carats. If the you
multiply ".56" times the specific gravity of Morganite (2.72),
you
get 1.53 carats. Closest carat weight wins. Not perfect, but good
enough when nothing else will do. David S. Geller
--
David S. Geller
President, Jewelry Artisans, Inc, Atlanta, Ga
Custom design and Repair Studio