RI with microscope

Jaap Bos wrote:

Pity, your URL seems to be obsolete

http://www.2spi.com/catalog/ltmic/ca...standard.shtml

....should work. (I had just moved to a new news composer that
had it's wrap set too short.)

Look toward the bottom of the rather long page
for the FH series.

But fluids of an RI 1.81, (as I recall from
literature about refractometer contact-fluids)
do contain e.g. phosphor and
will spontaneously ignite when they are dry.
Hardly something to work with in a non-lab environment.

Carghill's series H goes up throught 2.

Melts are used for higher R.I.

The test prodedure is exactly the
same once the melt is warmed and
the object is embedded.

Carghill's series FH
covers exactly the refractive index
that a CZ would fall under.

Yes, they are toxic, but they will not
ignite, and there is no other procedure that I know of
that will work for a curved surface of a very small
object. There is even the GH series of melts that
go all the way up to 2.31.

Another method would be measurement of the Brewster Angle. There is an
expensive machine sole by the Gemm. Assoc. of Great Britain for around
us$1800 (IIRC) or perhaps it could be a fun DIY lab project. At one time
i was gonna try to build one with some Toshiba superbright amber LEDS
and a large cardboard protractor. May work better on flats but I suspect
an estimate on cabs may be very close. I should also mention if this cab
is unmounted an accurate specific gravity would be useful.

Carl
1 Lucky Texan


m wrote:
Jaap Bos wrote:


Pity, your URL seems to be obsolete


http://www.2spi.com/catalog/ltmic/ca...standard.shtml

...should work. (I had just moved to a new news composer that
had it's wrap set too short.)

Look toward the bottom of the rather long page
for the FH series.


But fluids of an RI 1.81, (as I recall from
literature about refractometer contact-fluids)
do contain e.g. phosphor and
will spontaneously ignite when they are dry.
Hardly something to work with in a non-lab environment.


Carghill's series H goes up throught 2.

Melts are used for higher R.I.

The test prodedure is exactly the
same once the melt is warmed and
the object is embedded.

Carghill's series FH
covers exactly the refractive index
that a CZ would fall under.

Yes, they are toxic, but they will not
ignite, and there is no other procedure that I know of
that will work for a curved surface of a very small
object. There is even the GH series of melts that
go all the way up to 2.31.








--
to reply, change ( .not) to ( .net)

I have a tool called a reflectometer that measures cz's and other high ri
simulants. Mine is from Hanneman Lapidary, but I have seen another one that
was nicer looking and easier to work with but don't remember it's name.
They had them in the Roseco catalog for a while but it has been years...

Bill Kuykendall

PS Homebrewer, photographer, and jewelry guy here too. Really enjoyed
looking through your site! I'm bottling my Kolsch tomorrow and might brew a
Bitter tomorrow.

"Jack Schmidling" wrote in message
...
Learned something interesting about measuring RI with a microscope
today....

I tried measuring a CZ cab that I had just finished and came up with 1.32.

I then polished a slice of the material and came up with 2.1.

Moral of the story ( I think) this does not work on lenses, only through a
flat surface.

js

--
PHOTO OF THE WEEK: http://schmidling.netfirms.com/weekly.htm
Astronomy, Beer, Cheese, Gems, Sausage, http://schmidling.netfirms.com

"Carl 1 Lucky Texan"

I should also mention if this cab
is unmounted an accurate specific gravity would be useful.

The SG is as it should be for CZ. The problem was trying to measure the RI
directly (microscope) through the top. The lens effect produced an absurdly
low RI but turning it upside down and looking through the flat solved the
problem and produced the RI for CZ.

The discussion has been about other ways to measure RI for high refractive
material and so far, the microscope seems tough to beat. Glad I did not
waste my money of a refractometer. I was not aware of this limitation when
I was on the way to buying one.

js


--
PHOTO OF THE WEEK: http://schmidling.netfirms.com/weekly.htm
Astronomy, Beer, Cheese, Gems, Sausage, http://schmidling.netfirms.com

"m" schreef in bericht
...
Jaap Bos wrote:

Pity, your URL seems to be obsolete

http://www.2spi.com/catalog/ltmic/ca...standard.shtml

...should work. (I had just moved to a new news composer that
had it's wrap set too short.)

Look toward the bottom of the rather long page
for the FH series.

But fluids of an RI 1.81, (as I recall from
literature about refractometer contact-fluids)
do contain e.g. phosphor and
will spontaneously ignite when they are dry.
Hardly something to work with in a non-lab environment.

Carghill's series H goes up throught 2.

Melts are used for higher R.I.

The test prodedure is exactly the
same once the melt is warmed and
the object is embedded.

Carghill's series FH
covers exactly the refractive index
that a CZ would fall under.

Yes, they are toxic, but they will not
ignite, and there is no other procedure that I know of
that will work for a curved surface of a very small
object. There is even the GH series of melts that
go all the way up to 2.31.


Thanks for all this info. It will take a small fortune to buy the complete serie
;-(


Groeten,

Jaap

"Bill Kuykendall" schreef in
I have a tool called a reflectometer that measures cz's and other high ri
simulants. Mine is from Hanneman Lapidary, but I have seen another one that
was nicer looking and easier to work with but don't remember it's name.
They had them in the Roseco catalog for a while but it has been years...


Maybe it was the "Jewellers Eye", an analog instrument.
Or the digital version "JeMeter Digital 90" from Sarasota Instr.

But for a reflectometer you need a flat surface with a very good polish on the
stone.

Groeten,

Jaap