Subject: Suggestions on locating used gemological instruments?

From: [email-masked] (M B Wehr (Bruce))
Date: 2 Mar 1994 20:44:28 GMT

Howdy,

    I know this is off-charter for this group; but I find no more
    appropriate newsgroup.  Please bear with me; I'm simply trying to
    increase my chances of reaching somebody who may be able to help.

    In preparation for my G.I.A. Gem Identification course, I've learned
    that I need access to a small variety of instrumentation.  G.I.A.'s GEM
    Instruments Company offers all I need in kit form; for a hefty price. 
    I'm wondering if I can't find any or all of these items on the used
    market (I have a feeling it's a long shot, but worth a try). I need the
    following:

      1) Refractometer (w/RI liquids & polarizing filter)
      2) Polariscope (w/condensing sphere)
      3) Dichroscope
      4) Spectroscope
      5) Specific gravity liquids

    Other than knowing casually what parameter is measured by each
    instrument, I'm not intimately familiar with many of these items (I
    have no idea what RI liquids are, for example) - I just know what I've
    been told I need.

    Any suggestions as to where one might find these on the used market?
    You don't happen to have one or more of these items in your back pocket
    collecting dust, do you? :-)

    Thanks for any and all pointers (and offers!).

--
	      \       Bruce Wehr ([email-masked])     /            
*--------------\   Ford Motor Company - Electronics Division   /--------------*
 \ Electronics Technical Center - Powertrain Electronic Controls Engineering /
   *-- 17000 Rotunda Drive, Room B360, Dearborn, MI  48121 (313)248-5530 --*

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From: [email-masked] (Clive Washington)
Date: Thu, 03 Mar 1994 12:07:40 +0000

In article <[email-masked]>, [email-masked] (M

>     Howdy,

I used to do a lot of gemology, and believe me you can learn a lot by
not having the instruments!  It forces you to develop your basic skills.

If you're getting the official qualification, however, you will need
them.  I can't offer you a used source, but the following may be save 
you some money.

Don't buy the RI/SG liquids from the gem supply places, they are 
overpriced (at least in the UK).  Go to a lab supply company and
get 25-50 ml of the following:

Methylene Iodide
Bromoform
Monobromonapthalene

Try to do without Clerici solution if you can.  It's viscous, very toxic,
and can crystallize out at awkward moments.

The ordinary reagent grade liquids are ok.  One problem to watch out for is

that the bromoform may have 1-5% of ethanol as a stabilizer, and this 
reduces its SG so that quartz no longer floats in it.  If you put it in 
an ice bath and allow it to freeze until about 10% is still liquid,
then that 10% will have all the ethanol in it, and you can discard it.
Melt the crystals to get your pure bromoform, which should now float
quartz.

Put a small piece of copper wire in each liquid to pick up any coloration
due to free halogens.

I don't know what textbook you use, but in the UK Anderson's Gem Testing
is preferred.  I found it excellent.

Clive W.

Roll on rec. crafts jewellery!
-- 
!!!According to my contract, this place owns my opinions!!!

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From: [email-masked] (bill nelson)
Date: Wed, 9 Mar 1994 23:04:52 GMT

[email-masked] (M B Wehr (Bruce)) writes:
: 
:       1) Refractometer (w/RI liquids & polarizing filter)
:       2) Polariscope (w/condensing sphere)
:       3) Dichroscope
:       4) Spectroscope
:       5) Specific gravity liquids

You can get refractive index liquids from the better equipt jewelry
supply companies.  The liquids are a trivial part of the cost of the
refractometer.  You can also get the SG liquids from chemical or jewelry
supply companies.

The Dichroscope also uses polarizing filters - you can get them from
a scientific supply - but they may require special mounts for use in
the instruments.

I have never seen any of these on the used market. They are not common,
most jewelers do not own most of them. Unless you are an excellent 
machinest, you do not want to attempt designing and building most of
them.

Bill