Easiest & also most useful gemological tools to learn to use

[beaujolais]

Easiest & also most useful gemological tools to learn to use?

Ok, I've got the loupe down, no problem.

I want to learn more about all these stones I've collected. (I'm starting to sell the less loved ones off now, though). I tried to use a refractometer once - - oh, that seems impossible, impossible, impossible to learn. Also, I'm not wanting to deal with the carcinogenic R.I. drops. I think you need a live person to teach you how to use a refractometer and even that would take awhile.

What else is a useful tool and not crazy hard to learn.

 

[mastercutgems]

Re: Easiest & also most useful gemological tools to learn to

Way to go; it is a long journey; but it is fun

I know now I find the 100x microscope with all the different light types for color shift/change is a must as you can tell so much by the inclusion types or lack there of

Next you can go with filters like Hanneman gemological ones are good to narrow your field of determining natural, synthetics, etc. RI is still a good thing to know and it just takes practice and as long as you do not breathe in or smear the RI fluid on you; I do not think it is that bad; if in fear wear a mask and gloves and just do all your RI testing at one time...

SG is okay and useful, dichroscope is also okay and can be used on many gems; polariscope is cheap to make and also useful in narrowing the field.

But to be honest the RI and the 100x microscope is the most used in my lab. The if you want to get really scientific I also us the Challenger digital polarizing spectroscope with b&w monitor and your can get well above 1100 nanometers for testing absorption and fluorescing bands for checking elements in the gemstone to determine Be heating or may I say higher than normal reading of Be when it should not be there also for detecting other trace element that should not be there if you are determining diffusion, etc.

Also try to get you a modern GIA lab manual as you can many times find them on ebay form a person that dropped the class..

Many avenues to travel but nothing beats the feeling of confidence in testing your gems and knowing what is what... Just take a step at a time and build your lab with quality items and the most expensive is not always the best... just like the people on PS do with their gems... shop, shop, shop...

Most respectfully;

Dana Reynolds
ASG Certified Supreme Master gem Cutter #96cge42

 

[beaujolais]

Re: Easiest & also most useful gemological tools to learn to

Thanks so very much, Dana.

I really want to get a microscope ! I Love inclusions !

I don't know what a filter is - must go find out.

I have a young son, so did not feel good about using the RI liquid here. I also think I'd need live refractometer lessons or would I get a knowledgeable person to teach me how to use one?

Are polarizing spectroscopes hard to learn to use?

I really appreciate your encouragement and input. Thanks so much,

sonoma

 

[ChrisA222]

Re: Easiest & also most useful gemological tools to learn to

Sonoma,

There is an RI machine for sale that doesn't use the fluid. Its made by Presidium...I just checked, it is available on Amazon.com for $279. Not cheap, as a regular refractometer is about $100, but this way you don't have fluid to deal with. You just put the stone in the test area, and the RI is displayed on the digital readout. The other benefit of this machine is that it isn't limited by the RI of the fluid...this means that stones with higher RIs like Zircon or Demantoid will be able to be tested. Hope this helps. I haven't bought the machine for myself, I am considering it though.

 

[Lee Little]

Re: Easiest & also most useful gemological tools to learn to

On my table, the refractometer is the most useful, by far, besides magnification. Not really that hard to learn. Microscopes are much more expensive and are actually harder to master. Certain stones can be tricky on RI but most will tell you right away who they are. I use little fluid, keep it capped and have trained myself not to inhale when it is near. Generally it is rare that I get even a whiff of it.
I would try it again. Next is the SG rig, not difficult to learn either but RI is way more useful. Spectrum is very useful, however, quite difficult. Best regards, Lee

 

[beaujolais]

Re: Easiest & also most useful gemological tools to learn to

Thanks Chrisa,

that doesn't use the fluid. Its made by Presidium.. it is available on Amazon.com for $279. Not cheap, as a regular refractometer is about $100,

Well, if it is good to use and does the job, that sounds worth it, I think.

The one I tried, you had to - if I remember, read where the line fell on the scale and it seemed somewhat ambiguous to me. (I would have needed a live person to give me lessons with it.) I just looked on Amazon and someone said, about one similar to the model I used,: I have a hard time reading the refraction sometimes, and sometimes it comes in clear. The refraction chart you can find on the net has several types of gems pretty close in value, and this meter doesn't give precise measurements.

That was not the model I used or my review but it would have been spot on. It was really frustrating.

The one you speak of, that I just looked up, sounds really nice ! (Please get it and report back - )

I'd consider getting it, myself. I'm dying to get a microscope & look at inclusions, though.

(Why do I always find expensive hobbies? )

Thanks so much for the info.

---

Hoping some of the professionals on this board tell us what they think of the digital Presidium that Chrissa brought up.

 

[Arkteia]

Re: Easiest & also most useful gemological tools to learn to

If someone could also post links to microscopes which could be easy enough, but of good quality and easy for a person who is very far-sighted. It has to have separate adjustments for each eye and, preferably, a projector screen. I know they are expensive but in case of any vision device, I have to invest.

 

[desertgem]

Re: Easiest & also most useful gemological tools to learn to

I have both the Presidium "Refractometer" which is really a Reflectometer and a GIA Duplex II refractometer. I bought the Presidium because I am interested in the area above 1.81 and also it is easy for anyone to use to get a "close" reading. I have many times compared the Presidium with the Duplex and below RI 1.81, the duplex wins easily, with the presidium off a small percentage. This is acceptable to me most often, and my son who shares my interest often had a horrible time ( due this eyes ) getting a RI , is really happy I bought one. The gem has to have a faceted surface for the presidium to use. If the stone is mounted and has a facet ( table) away from the setting, it can be measured with the Presidium ( you may have to make a support structure such as from a polymer) Also there is no fluid ( modern fluid is safe but smelly), nor possibility of damaging the soft glass of the regular refractometer since it just has a small pinhole for the light.

Also on the question of stereo microscopes, only one eyepiece is adjustable ( usually the left ) as the person is suppose to close that eye and focus sharp with their right eye and then close it and use the adjustment on the left ocular to make its vision sharp, then you don't have to adjust anymore unless some one else uses it.

Specific gravity is also a nice reference to have and is difficult to design a device to test it easily. Basically , it is a measurement determining a gem weight in air ( easy) to its weight in water (difficult) and calculating ( hard to some). Here is a device that is easy to use. Also developed by Dr. Hanneman.
http://www.mineralab.com/Hanneman.html

It is limited to just under a ct small.

Jim

 

[beaujolais]

Re: Easiest & also most useful gemological tools to learn to

Desertgem: Do you mean the digital Presidium (the one without the liquid)? Tx.

 

[desertgem]

Re: Easiest & also most useful gemological tools to learn to

Yes, at least it has a digital readout rather than an analog meter, so I am sure that is what you are asking. It is fast, turn it on, put the gem facet down over the pinhole ( there are 4 guide lines to line it up), put the plastic cover over it to close off external light, and the digital RI shows right up.

Jim

 

[chrono]

Re: Easiest & also most useful gemological tools to learn to

The refractometer is a must and one of the most useful tools out there for coloured gemstones. You'll get far less use out of a microscope. Both will require training (know what to look for) but I cannot stress enough getting the refractometer over everything else. It will help distinguish a gem type over another, help spot synthetics and simulants and more. I have no experience with the liquidless version though.

 

[beaujolais]

Re: Easiest & also most useful gemological tools to learn to

Thanks Desertgem. Yes, that is what I was asking. OK, I can deal with the digital one, it sounds. I think I'll ask for/get that for myself for Christmas this year.

Thanks Chrono.

 

[mastercutgems]

Re: Easiest & also most useful gemological tools to learn to

I am sorry but I have to disagree as the microscope is THE most useful of all the tools as with synthetics the way they are today; the mineral in question will have the same RI or so close a standard refractometer will only get you so close as we are dealing in points and the typical refractometer will only get you within .1 of the index and not like the machines they use in the lab that will give .01 of the RI...

All people that test on a regular basis and use the tools of the trade to make their living as well as the big labs will tell you... The 100x or greater microscope tells them more of the crystalline structure, inclusion, growth habits of the crystal, heating, non-heating, than any other tool they have...

I mean no disrespect but that is something you must learn to identify all those things to determine natural over synthetic; also if you use the refractometer the dichroscope, SG, polariscope, hardness tester, etc. even the spectroscope on a synthetic sapphire you will get readings so close you cannot determine natural over synthetic; but under 100x or better you can determine synthetic over natural by the growth as well as the inclusions in the gem; also it is one of the key tools in determining heated gems...

So this is one time I must say what I think as it is a tool I make my living by to determine many gems and their natural/heated/treated/untreated state. It is also great for determining flux filling, etc. which has been brought up here more than one time... As a refractometer cannot determine anything but refractive index... well maybe polarization if you know how to use it as it is a great tool but not a tell all for gemstone identification...

This is one of those things that I am sure many will either agree or disagree with and that is cool We can all agree to disagree at times

Most respectfully;

Dana Reynolds
ASG Certified Supreme Master Gem Cutter #96cge42

 

[ChrisA222]

Re: Easiest & also most useful gemological tools to learn to

desertgem: are you sure the Presidium is a reflectometer? I saw that they made a reflectometer...its available for sale, I think I saw it on Amazon. They also offered the Presidium refractometer, and the new one is the Presidium Refractometer II.

Sonoma, I know somoene who uses it, and loves it. I actually bought the first model and returned it before I used it, because I heard there was a new one out and it wasn't that much more expensive. I cant remember exactly what the differences were but at the time it was enough for me to sell the first generation one that I bought.

I think its a great option as the RIs arent limited to the fluid...1.81 I guess...and no fluid and no mess and its supposedly easy. It has to be a facetted gem though, It wouldn;t work on a rough piece I dont think.

Sonoma: Hope this helps, I want to get one for myself! I like your Christmas idea, maybe we can buy one for each other!

 

[chrono]

Re: Easiest & also most useful gemological tools to learn to

For a person who is just learning to ID stones, I feel that a refractometer will get better usage than a microscope. I agree with you 100% that a good microscope goes a long way but you MUST know what you are looking at / looking for. It takes a lot of experience to spot the inclusions, understand the different inclusions and what they mean, or even the implications of what it represents. For an expert, a microscope is indispensible but for a novice, it will likely just confuse him/her further without something explaining what are the dots, gashes, lines and etc. It's like learning to walk - start with small incremental steps. A refractometer first helps narrow down what the stone might be. Is it a beryl? Is it a garnet? Is it a spinel? Then the other equipment like a microscope comes in next to determine if it has been clarity enhanced, heated, and etc.

 

[PrecisionGem]

Re: Easiest & also most useful gemological tools to learn to

Get a refractometer, and not one of those cheap $100 ones from eBay. These will only frustrate you and most likely give you incorrect readings. Good tools are not cheap, but don't waste your money on junk. There is a reason that pro's buy quality. I don't know any professionals who use and recommend the Presidium for most stones. They are useful only for stones above 1.81 RI, which there are very few you will run into.

But you will need some reference to compare what you see and measure. I recommend a software called GemTools Pro (http://www.gemologytools.com/). With this you enter what you know, and the program shows you the possible stones.

In identifying stones, normally you are not really finding out what something is, you are eliminating what it is not. With the refractometer, you can also identify the optical character and sign, but you need to do a little math for this. I wrote a program to perform this calculation for you. I used to have it on my site for download but took it off as know one ever downloaded it. If you want it email me and I'll send it to you free. I have it also as a Numbers spreadsheet for the Mac, but I suppose you could run it on Excel if you are using Windows.

 

[ChrisA222]

Re: Easiest & also most useful gemological tools to learn to

Gene, Why is the Presidium refractometer only good for stones over 1.81? It should work on any stone that has a table, no? She was looking for a refractometer without the fluid...and, I was looking for one for myself as I'd much rather pay more and get something easy to use, not messy, and will give a reading on any facetted stone, regardless of if itis above 1.81 or not.

Before I, and the OP go and buy the unit, can you tell us why you are saying it isn't good with stones below 1.81?

 

[RedSpinel]

Re: Easiest & also most useful gemological tools to learn to

Easiest & also most useful gemological tools to learn to use?

Ok, I've got the loupe down, no problem.

I want to learn more about all these stones I've collected. (I'm starting to sell the less loved ones off now, though). I tried to use a refractometer once - - oh, that seems impossible, impossible, impossible to learn. Also, I'm not wanting to deal with the carcinogenic R.I. drops. I think you need a live person to teach you how to use a refractometer and even that would take awhile.

What else is a useful tool and not crazy hard to learn.

I did this backwards, as I actually bought a refractometer before I bought a simple 10x loupe! But those 2 purchases were pretty close together. The refractometer was more important to me at the time, so I didnt get burned by purchasing fake or improper gems.

I had watched 2 jewelers use refractometers right in front of me, and they let me look into it, all before I ever bought my own, so I already knew how to use it. I've never had any problems with the mid-priced one I bought for around $100(give or take). It alweays been 100% accurate, and pretty easy to use. It came with a screw in light that illuminates the internal viewing area, but you do have to move your head around a bit to find the line and see where it sits on the graph there. The only problem I ever had was when I was checking a few zircons I had bought, and they didnt even show up on the refractometer. But then I found out that means they are real, because their refractive index is so high its actually above the level the refractometer can read(higher than most refractometers I've seen)

 

[PrecisionGem]

Re: Easiest & also most useful gemological tools to learn to

Gene, Why is the Presidium refractometer only good for stones over 1.81? It should work on any stone that has a table, no? She was looking for a refractometer without the fluid...and, I was looking for one for myself as I'd much rather pay more and get something easy to use, not messy, and will give a reading on any facetted stone, regardless of if itis above 1.81 or not.

Before I, and the OP go and buy the unit, can you tell us why you are saying it isn't good with stones below 1.81?

They are not that accurate. The reason I say over 1.81 is because thats the limit for a standard refractometer using fluid. But how many stones are above that? Zircon maybe a few others that you guys here are not buying anyway. The other problem is the Presidium and other similar devices do not tell you if the stone is single or double refractive, what the optical sign and character are or what the birefringence is. These are all very important measurements you make with a standard refractometer.

What's the issue with the liquid? It is not messy or difficult at all. Put a drop on the glass then place the stone on it. When you are done take a tissue and wipe both off. Not messy or difficult at all. A proper refractometer with have a true sodium wavelength light and a polarizing filter. These cheap $100 will give you a reading, but it's not accurate nor always easy to find a reading. Try taking a reading on a smaller stone, or one with a small table on a cheap unit and you won't find the shadow line on the scale.

Like anything else in life you get what you pay for. Years ago in Tucson I set out to buy one, and was able to actually use many different models on my own stones. I ended up buying the Eickhorst made in Germany. Now this is a very expensive tool close to $1000, you don't need to spend this much to buy a quality tool, but the Chinese ones you see on eBay I would stay away from. They will have cheap glass that will quickly scratch, scales that are not properly calibrated, no sodium light source and cheap optics that will not be consistent across the entire scale. The Eickhorst is accurate to 0.005 with a scale with twice the resolution of any other refractometer on the market.

 

[PrecisionGem]

Re: Easiest & also most useful gemological tools to learn to

These are the stones that I could find that would have a RI higher than 1.81 that couldn't be measured with the standard refractometer:

Allanite, Bastnasite, Benitoite,Bonamite,Cerussite, Zircon, Gaspeite, Hancockite, Linarite, Monazite, Painite, Piedmontite, Scorodite, Siderite, Smithsonite

So which one of these do you commonly need to measure? Pretty much just Zircon.

 

[desertgem]

Re: Easiest & also most useful gemological tools to learn to

I think Demantoid garnet ( 1.85-1.89) and possibly even Spessartine garnet ( 1.79-1.814) should be added to the Zircon.

 

[Richard M.]

Re: Easiest & also most useful gemological tools to learn to

Some of the most popular gem garnets have RI's over 1.81 like almandine, demantoid and topazolite),and many spessartines especially when they are mixed with almandine like the red-hued ones. I bought an older Presidium reflectometer to attempt to measure them but have found it glitchy, unreliable and untrustworthy. A whole lot depends on the quality of the polish on the surface being measured, cleanliness and the machine's calibration. I find it necessary to recalibrate my Presidium after each measurement. I agree that investing in quality gemological instruments is essential and a refractometer is one of the most-used such tools. Buy a good one to start with.

Important gems other than zircon that are OTL (over the limit) with standard RI fluid (assuming one is using the most expensive 1.81 type and not the 1.80 version) are diamond, sphalerite, sphene, and many widely-sold synthetics like cubic zirconia, YAG, Fabulite (strontium titanate), and linobate, sold as Titania.

If one hunts down Dr. William Hanneman's "Guide to Affordable Gemology" (the second edition is still in print) it contains plans for making your own refractometer that will measure any RI without liquid. Warning: it takes up a bit of room and requires a bit of learning.

Richard M.

 

[minousbijoux]

Re: Easiest & also most useful gemological tools to learn to

Wow, so nice to have so many vendors/cutters responding on this thread - thanks for initiating it, Sonoma County.

My question: there is a big price difference between $100 ebay refractometers and the $1000 Eickhorst models. So can you all recommend one thats less than $500 (preferably even lower) and good to use?

 

[Richard M.]

Re: Easiest & also most useful gemological tools to learn to

My question: there is a big price difference between $100 ebay refractometers and the $1000 Eickhorst models. So can you all recommend one thats less than $500 (preferably even lower) and good to use?

The only refractometer I've ever used (35 years!) is a GIA Duplex II and it's still like new. So that speaks to its durability but the current price in dollars is pretty high if you buy them new. They're often sold used on EBay but I don't recommend that venue for beginners because there can be issues they're not aware of. If I were starting out now I'd give some thought to the Gem-A package sold in the U.S. by Mineralab. I'm not sure if it's OK to show a link here but it's easily Googled. It's from the Gemological Association of Great Britain and I've heard only good things about it -- maybe some Gem-A people here can comment.

The downside is it's close to $650 plus shipping with the sodium wavelength lamp and 1.81 liquid. Still, I don't think I'd opt for anything of lower quality. While I can't claim to have used/tested every machine on the market, gemology requires the kind of consistent precise measurements that "budget" equipment seldom delivers.

Richard M. (Rick Martin)

 

[minousbijoux]

Re: Easiest & also most useful gemological tools to learn to

Thanks, Rick. That's the second recommendation I've gotten for the Gem-A model. I guess I'll need to sell a few more stones in order to buy one.

 

[chrono]

Re: Easiest & also most useful gemological tools to learn to

Thank you for the recommendation. More or others are always welcome. I'm sure there are many enthusiasts who do not have the budget for a $1K unit, yet need/want a consistent good perfoming piece of equipment that will not break the bank.