Gem identification kits?

[tsavvy]

I''m interested in putting together some tools for gem identification to augment some other purchases and would appreciate some input/guidance. There are a few on-line that look decent without being really expensive - does anyone have experience with the following kits or recommendations for a good kit?

Rio Grande - Gem ID Starter Kit $135 This one seems pretty basic, but may be adequate initially.
-Chelsea filter
-Color corrected loupe
-Calcite dichroschope

Pretty Rock - Study Gem ID Kit $475 I''m leaning toward this one - it seems like the best deal under $500.
-Gem Lab Refractometer
-10gm Bottle RI Liquid
-PR Travel Specific Gravity Kit
-Tabletop Polariscope
-Pocket Spectroscope
-Pocket Dichroscope
-Jadeite Filter

Pretty Rock - Travel Gem ID Kit $150
-Pocket Polariscope
-Pocket Dichroscope
-Jadeite Filter

 

[tsavvy]

*bump* anyone...anyone?

If I splurge, there is the $1,900 kassoy student ID kit -- does anyone know if the scopes and filters in this kit are much better than the ones that come with the prettyrock.com kit? None of them kit contents are branded, so it is hard to search for reviews on the quality of the components of each kit.

 

[chrono]

The second one sounds like it has everything but again, you will have to know how to use them for it to be worth the money.

 

[deorwine]

I don''t have any of those kits, but I do have the book Gem Identification Made Easy which I LOVE and very much recommend (maybe your library has it if you don''t want to spring for it; I originally got it from the library and then had to buy my own copy). It basically recommends the contents of the Starter Kit as a the first step (triplet loupe, Chelsea filter, dichroscope)... you can tell a lot from those, and the book tells you how. As a second step it recommends the spectroscope, etc.; as well as a dark-field loupe and an immersion cell. It also has some recommendations for specific components, though not for kits.

I would myself just get the book, read it, and buy instruments one by one depending on what I wanted to identify (are you really going to use a jadeite filter a lot?) but of course you should do what will work best for you (and buying a kit is probably a little more cost-effective).

 

[tsavvy]

Chrono - Thank you for the response. I will get PrettyRock''s study kit and see how it goes. I''ve found a few sites that provide directions and photo examples for using the equipment, so hopefully all will go well

Deorwine - I appreciate the book suggestion and will check it out. I''m getting an assortment of rough and thought it would be fun to learn how to analyze/test the stones. Won''t be quitting my day job, though

 

[PrecisionGem]

I can''t really comment on the Pretty Rock ID ket, but it does seem rather inexpensive. My refractometer cost $990, and my spectroscope was over $2000. One thing I can tell you, with a spectroscope, you need a very good light source. Specific gravity can not be measured very accurately unless you have a very accurate scale, one that is accurate to the third decimal place, or you are measuring pretty large stones. A polariscope is not as complicate as the other instruments, and it''s basically 2 polarizing lenses turned 90 degrees to each other.

 

[PrecisionGem]

The first option you have listed does have the book mentioned above. This is an excellent book, and one you will want. I would start with this first option, and then consider a refractometer next. If you are trying to identify rough, the refractometer will not do you any good however, unless you can polish a flat surface on the stone.

 

[tsavvy]

Thanks, Gene. Your input is valued -- I saw that there are very expensive refractometers, spectroscopes, microscopes, etc., but was not sure if the less expensive options were junk and virtually worthless, or just not as nice yet still serviceable.

Regarding scale accuracy for specific gravity measurements, do you mean a scale accurate to 0.001 carats is necessary? I have found some of nominal price that are accurate to 0.001 grams or 0.005 carats, but to obtain accuracy to 0.001 ct it looks like the scales go into the $1,000+ range.

 

[PrecisionGem]

The problem with specific gravity and scale accuracy is this. If you have a stone that weighs 1.50 cts. and your scale is accurate to 0.05 cts. and you measured the weight of the stone in water, your specific gravity could vary by this much:

2.583 to 3.625

That''t too large a range to be useful.

With an accuracy of 0.005 it would be:

2.951 to 3.051

With an accuracy of 0.001 it would be:

2.99 to 3.010

As your stone gets heavier, the accuracy will go up.

I''m working on a program that is almost done to help you do the specific gravity calculations along with the range, based on the accuracy of your scale, and will also have a calculation to determine the optical sign and character using readings from the refractometer. Should have it ready for download on my site in a few days. The program will run on a Mac, or Windows machine.

 

[PrecisionGem]

I bought much of my equipment several years ago at one of the Tucson shows. Here I was able to actually use many of the different name brand instruments, and ended up buying the System Eickhorst, which are made in Germany. The inexpensive spectroscopes are really useless. With out spending at lot money, the OPL spectroscope is your best bet. I think it may be around $100, but then you will need a stand and light source. A fibre optic light source is by far the most useful.
With a refractometer, you really want a sodium light source, which the cheap units will not have, or most likely will not have any light source.

 

[Largosmom]

I''m following this thread, as are others, I am sure...for future reference. I''m picking up the book first for some reading.

Thanks for sharing the information on the type and quality of tools needed and accuracy of some of the data.

 

[tsavvy]

Thanks for the SG explanation, Gene. I''ll be checking your site for the program - I already check it regularly for new gemmies, so this just gives me an excuse for even more frequent visits

Eickhorst equipment is out of my budget for the time being -- this is just a hobby for me, so I was hoping to acquire a variety of tools for under $1,000 -- with your equipment, that would be the minimum for just one item!!

 

[elmo]

Date: 11/25/2009 1:34:43 PM
Author: tsavvy
Eickhorst equipment is out of my budget for the time being -- this is just a hobby for me, so I was hoping to acquire a variety of tools for under $1,000 -- with your equipment, that would be the minimum for just one item!!

For well under $1000 I'd assemble what you need piece by piece selectively from ebay. GIA gem instruments tools come up for sale all the time, they are usually not cheap but still a fraction of the new cost. Like Gene says eventually you'll need a good scale, and don't forget a good microscope (when you have another thousand or two to spend

).

 

[Pandora II]

I ditto a copy of that book and buying pieces one at a time.

For a loupe, you need to get one with a black casing - I really love the Belomo loupes, they''re not expensive and yet the optics are first-rate (Carl Zeiss makes the lenses).

Some stone tweezers are also an essential - I like the ones with a horizontal groove where you can hold a girdle easily. I HATE the ones which lock - far to easy to ping stones all over the room. I''m also not a fan of ring-style stone-holders.

I''ve definitely found that you get what you pay for with a lot of equipment. Ebay is worth stalking. I picked up a Gem-A sodium light for a refractometer for £3 GBP - they cost over £50 on the Gem-A website.

 

[RockHugger]

I got my refractometer used for 55$. It works very well and has been right so far. of course you do need other goodies to ''be sure'' but a refractometer is a good start.

 

[PrecisionGem]

I just posted a free program that I wrote on my site to help with some gemological measurements. The program will help you calculate specific gravity, and show you the amount of error that could be in your calculation.

Also, for those with a refractometer, the program will calculate the optical character and sign from your RI readings. This is very useful information in gemstone identification.

It''s available for both Mac

and Windows

Here''s a link to download the free program

http://www.precisiongem.com/FileDownload/FileDownload.html

 

[chrono]

Thanks, Gene.

 

[tsavvy]

I am taking Elmo''s advice and patiently waiting for some quality identification equipment to pop up on ebay for a decent price. I do have a Belomo loupe which was bought after reading another of Pandora''s recommendations awhile ago

and some assorted tweezers.

Thanks, Gene, for posting a link to your software. I downloaded the mac version and it looks very easy to use!

 

[Largosmom]

I am up to a book, a set of digital calipers that were marked down (needed a battery), a pair of tweezers, a stone holder, and some storage boxes.

 

[lelser]

One thing I don''t see mentioned is a darkfield loupe. It''s what I use instead of a microscope on travels, and makes it easy to see inclusions, glue lines, zoning, etc.

Dicroscope is critical, as is the OPL. Unless you want to invest the time to get REALLY good with a spectroscope, you won''t. The OPL is by far the best value for money.

My friend in Switzerland, who also sells in Tucson, has the best mix and match gem kits around.

If you''re buying at shows, not just testing at home you will simply never do the SG test. As Gene says, it requires better scales and larger stones than most people have.

http://www.free-form.ch/tools/gemology.html

He''ll build any tools you like into the zip case, and that''s how I carry my kit. It says "I''m a secretary, ignore me" instead of "I''m a gem dealer, rob me" like the porto-labs do

Cheers,

Lisa

 

[Largosmom]

I'm bumping this up because I am ready to buy a couple more identification tools and have some questions.

1) I'm definitely getting a chelsea filter and dichroscope. Are all the calcite dichroscopes basically the same quality? There is a fair price difference from what I see on ebay versus vendors say, on amazon. Same with chelsea filters, is there a quality difference between different products?

2) Is there a source for some type of tweezer with either a bit of rubber on the tip or a groove in the tweezer? I've seen reference to both, but haven't found them. I'm not having the best luck handling my thin locking tweezer and I have also used the stone holder with prongs, but it's hard to look into the stone well with those.

3) Is there a source for the Hodginson book on Visual Optics? I read a bit about it and am fascinated.

4) In addition to the dichroscope...what next? I'm not ready for a refractometer just yet...I'm thinking a spectroscope and after reading "GEM Identification Made Easy" I found there are two types...prism and diffraction grating. I remember using these types of instruments in either high school or college, but it's been quite a while since then. Is one more accurate than the other? Is there a best type to use?

5) Next books...I'm getting Gemstones of the World (new fourth edition)...what else would you recommend next?

Thanks much!

Laura

 

[virgoruby]

I would also appreciate recommendations of good gem reference books... TIA!

 

[PrecisionGem]

The best reference to have is a program called "Gemology Tools Professional". It''s a must have for gem identification. You make observations and measurements with the equipment you have, then enter what you know about the stone into the program, and it shows you possible gems it could be. Gem identifications is more a process of elimination the identification. I use this program all the time.

If you are thinking of either a spectrascope or refractometer, get the refractometer. It will help you identify much more, and is simpler to use. With a refractometer, and my free software called GemLab you can find:

determine single refractive from double
find the refractive index
Measure Bifringence
Optic Sign
Optic Character

Enter these along with the color and other observations into "Gemology Tools Professional" and you should be able to identify most stones.

 

[Largosmom]

It sounds like a good program, but it won''t run on my computer, unfortunately as I have a mac.

I did download your software, but have no idea what to enter into the fields yet.

Regarding the dichroscope...are they all basically the same quality?

 

[PrecisionGem]

I have a Mac too, but have Windows running on it too, just to run this program. You can either use Parallels or Bootcamp to install Windows on your Mac. Parallels let you run both OS X and Windows at the same time.

You don''t need to spend a lot on a dichroscope, the more expensive ones will just get you a brighter larger image.

You''ll need a refractometer to enter your measurements in my program. Just to play around with it, try using these values.

Measurement 1: 1.62 and 1.64
Measurement 2: 1.62 and 1.645
Measurement 3: 1.62 and 1.639


From these you will get an Optic sign, Optic Character and Bifringence.

 

[Largosmom]

Thanks Gene, I''ll give that a try tomorrow.

I haven''t gotten around to running windows on my mac yet...was waiting for Windows 7 to come out and now just haven''t yet gotten around to it. I have some other software that I''d like to run, so I really should.

Appreciate the advice on the tools, I''ll take a look around for a refractometer.

Laura

 

[Arkteia]

I think it is a great topic. I read Matlin''s book and find it extremely helpful. I am going to use Gene''s program. But...can anyone put together and recommend "Gem Identification Kit for Idiots"? Simplicity is the main factor, not the price.

 

[PrecisionGem]

Laura, I think you would be better off with just Windows XP on your Mac. Windows 7 will eat up a lot of hard drive space, and needs a lot of memory. Running it side by side with OS X will really bog things down. I''ve used Windows for 20 years, and switched to the Mac 2 years ago. At home I have only one thing I do on Windows any more, and that''t the gem program.

For tools, aside from what is recommended in Matlin''s book; loop, Chelsea Filter, and Dichroscope, all of which are pretty inexpensive, I''d start with a refractometer. Buy one that has a good built in light source with a sodium light source (yellow light) or filter. Messing around with little pen flash lights is a pain in the neck.

 

[Largosmom]

Funny, though off topic, Gene..I''ve got about the same amount of Windows and Mac time that you do!

Back on topic though...thanks for the recommendations, I''ll see what I can find.

Laura

 

[tsavvy]

Largosmom: In order to not damage my gems, I have tweezers w/ teflon-coated tips from Kassoy and fiberglass calipers from Silver Supplies. I noticed you asked about Visual Optics -- Richard Sherwood posted about that method a long while back. Also, regarding Gene''s software suggestion (thank you, Gene!), I run Parallels to use a lot of windows programs on my computer. It works perfectly. DH and son both use bootcamp without any problems. I prefer parallels because I can keep it running in its own window while still having all my mac programs open.

I bought a used GIA refractometer and polariscope on ebay. I may get a better refractometer in the future and resell the GIA one, but it should hold its value well. I''m going to order a darkfield loupe, calcite dichroscope, chelsea filter (appears to be the same as a jadeite filter), 20x loupe, and carat scale this month. I''m waiting for a vintage prism spectroscope to show up on ebay, but will buy an OPL if the search goes on past two months. The OPL that comes in the table stand along w/ a separate light looks like it would be the easiest to use. The supplier Lisa Elser recommended above has really good prices, but I decided to save some money and get the more expensive pieces used. In the next six months or so, I''d also like to get a microscope but there''s no hurry on that.

A few more books have also made their way into my library:
Gemstone Identification Made Easy - super informative and the best of the bunch so far.
Faceting for Amateurs by Glenn & Martha Vargas - Great book. I highly recommend it. Very enjoyable to read with a ton of information. The authors explain a lot about the different properties of gemstones and relates those properties back to faceting. I also have a few books on meetpoint faceting that are useful. The interest in faceting is what spawned the interest in gemstone identification.

Secrets of the Gemtrade - I''ve noticed that this book gets quoted around here when talking about price points and preferred colors of different stones. It was an interesting read, but I would have liked more detail

Once I''ve mastered the refractometer and spectroscope, this book will also be added to the library: Tables of Gemstone Identification.