Calling Marlow, refractometer has arrived.

[needfullshinythings]

Hi Marlow, it arrived today. 1 problem though, the instructions are in German. So therefore I am going to need a little extra help please. I do have my sapphire to run a test on 1st as we already have a result to compare with. Give me a shout when you have a bit of time free. TIA.

 

[Marlow]

Here I am!! And I speak German

O.k. very easy

First clean the stone.

Turn on the light and put the pol filter ( it is like a srew ) on the lens.

Open the refractomer - you see a glass window ( BE CAREFUL it is very soft glass!!! )

Put a tiny drop of this liquid ( less then 1 mm diameter is enough! ) on the FIRST QUARTER of the glass.

Put the stone with the table facet with a tweezer carefully on the tiny drop. Look through the lens - what do you see???

Your sapphire- tell me the results.

 

[needfullshinythings]

I get a green line at 1.77 Marlow, sound right ?

 

[Marlow]

Sounds perfect - and the red line - use the filter please...

 

[needfullshinythings]

I get a red line 1.78, without the polar filter on. sound good.

 

[Marlow]

No, this is to high for sapphire - 1,762 and 1,770

How large is the stone ? It took me a bit time to find the right position on the glass. But it will work, don't worry.

I leave office now - in two or three hours "I'll be back" !!

 

[needfullshinythings]

OK Marlow, I will keep practicing. speak to you later, many thx.

 

[chrono]

Marlow,
Appreciate your helping out. When this is complete, I'd like to add this thread to one of the stickies because it is a good reference material.

 

[minousbijoux]

It would also be great if you could share the manufacture of the refractometer, and how you find using it, nfst. And Marlow, if you have worked with multiple types of refractometers, it would be great to hear which you think are easier for consumers like us to use (in other words, those of us who don't have hours to test, retest and clean... ) Thank you both!

 

[needfullshinythings]

Hi Minousbijoux, thank you for asking. I am more than happy to share all information with the community. Here is the manufacturer
Mueller MGR-181 Gemological Refractometer.
My experience so far = it has taken my eye a little time to get used to finding the lines that show up and also the position that the stone needs to sit on the plate. An enjoyable process so far.
I will let Marlow add an educated opinion later as to where the tool sits in the quality list.

 

[Marlow]

Here is a german company:

http://www.kruess.de/shop/Gemstone-Refractometers:::11.html?language=en

Look at the third refraktometer - looks identical as the Müller tool and has the same technical details. Double price. I tryed them in a show - no difference.

The Müller I use has a good quality - I would call it a student instrument - enough for what I need it - only "problem" is the Anderson liquid - after a few year the sulphur cristallize and so the RI is wrong or it is like a sand grain and the gem has no contact?

You can put the bottle in an espresso cup with hot ( not boiling!) water - the cristals melt and it works again.

I have some "masterstones" ( garnet - a leuco grossular, a corundum ) - I measure this one first.

A super tool is a digital refratometer as a second tool - for gems higher then 1.81 RI - problem is you get only ONE result - you need other tools like dichroscope and polariscope.

http://www.mineralab.com/Gem-n-Eye.htm

More later....

 

[ephsea]

Needfullshinythings, you may also want to look over at the "other forum" which shall-not-be-named that has "Gem" in it's title. There is a sticky over there on how to use a refractometer. Marlow's over there, too

 

[needfullshinythings]

Evening Marlow, thank you for the info.
Back to the testing. I think I made an error earlier by removing the polar filter after the 1st reading. I restarted the process and placed the stone in the centre of the plate, this time the green line stopped on just over 1.76 and the red line was clearly visible on 1.77. I then rotated the stone 90 degrees until I had checked it through its 4 positions with the same result.
I then tried the mystery stone ( possible tourm ) and was only able to get 1 reading which was just under 1.64 ( 1.638 ish )
Was I doing something wrong or just getting ahead of myself ? TIA.

 

[Marlow]

Yes, they have top tutorial video.

I am a user!! I learn a lot on GO and a lot here!!! I try to buy better gems - better quality - here I get a lot of input!!! I like this very much!

 

[needfullshinythings]

Oh well ephsea, shows how much of a newb I am as I don't even know its name !!! I stumbled across this one purely by chance and never bothered looking for any others. No point ending the thread as there may be others like me who only use this site and could find the info usefull.

 

[Marlow]

Evening Marlow, thank you for the info.
Back to the testing. I think I made an error earlier by removing the polar filter after the 1st reading. I restarted the process and placed the stone in the centre of the plate, this time the green line stopped on just over 1.76 and the red line was clearly visible on 1.77. I then rotated the stone 90 degrees until I had checked it through its 4 positions with the same result.
I then tried the mystery stone ( possible tourm ) and was only able to get 1 reading which was just under 1.64 ( 1.638 ish )
Was I doing something wrong or just getting ahead of myself ? TIA.

The stone has a good contact to the glass?

In a very very very very very very rare occasion it could happen that the table facet is exactly vertical to the c-axis - don't think so!

Or did you forget to use the pol-filter - turn it like an on/off button - to the left - to the right. Keep it on the lens

Write down what you see - the position, RI red and green line - will help you a lot.
You will need it with a Topas or Chrysoberyl

 

[needfullshinythings]

I didn't do the twist bit, will try that now Marlow. Back in a minute . Thx.
I see now Marlow, 1.62-1.64 ish. When I twisted it to the right it made the second line appear, although both lines are green !!!

 

[Marlow]

Tourmaline!!!

I will check it at home with the green lines

 

[needfullshinythings]

Damn, that means someone wont be eating their laptop !!! Great stuff Marlow, now I need to get some more training stones

 

[Marlow]

Loupetroop!!!!

 

[Marlow]

It would also be great if you could share the manufacture of the refractometer, and how you find using it, nfst. And Marlow, if you have worked with multiple types of refractometers, it would be great to hear which you think are easier for consumers like us to use (in other words, those of us who don't have hours to test, retest and clean... ) Thank you both!

The tools I post are easy to use and cheap in a positive way - I tried Krüss instruments - microscopes and spectoscope you see the difference - no question!

For cleaning the glass a the refractometer I use the wet cleaning papers for glasses - you should do this after using course of the sulphur.

You don't needmuch time and it is fun - you will love the smell of sulphur and iodite - gemmologist Chanel No 5

 

[needfullshinythings]

Thx, I need to make myself a member. I have seen most people listing on there but i don't know the site, will investigate now.
Thx again Marlow, no doubt I will have more questions soon
lmao Marlow, I got a very good whiff when I opened it. Maybe tooo god a whiff !!!

 

[digdeep]

It would also be great if you could share the manufacture of the refractometer, and how you find using it, nfst. And Marlow, if you have worked with multiple types of refractometers, it would be great to hear which you think are easier for consumers like us to use (in other words, those of us who don't have hours to test, retest and clean... ) Thank you both!

The tools I post are easy to use and cheap in a positive way - I tried Krüss instruments - microscopes and spectoscope you see the difference - no question!

For cleaning the glass a the refractometer I use the wet cleaning papers for glasses - you should do this after using course of the sulphur.

You don't needmuch time and it is fun - you will love the smell of sulphur and iodite - gemmologist Chanel No 5

le parfum de l'amour....... we all know this, right?

 

[Marlow]

Yes, in a gem show - use it as a perfume and they think you are an expert ( don't do this it is toxic!!!! )

 

[needfullshinythings]

Good morning Marlow, many thanks for the help yesterday. I found it a surprisingly enjoyable process, now I need more stones !!!
I made myself a member of LT but am not 100% sure what I should invest, or the size that I should get for practice purposes.
My budget is not huge so I would appreciate any thoughts on this subject Marlow.
How much, how big & any vendors that you would recommend would be greatly appreciated.
I made a list of 5 stones last night that I should get, Spinel,Aqua,Peridot,Emerald & Beryl. Would this make sense to you Marlow ?
Many thx Marlow

 

[Marlow]

Look at Thaigemstore and try to buy some cheap stones below 10 Dollar - 0,99 ct auction - enough to get practice.

Or you buy them, check them and send them back !!!! Just a tiny little unfair

http://www.ebay.com/itm/ONLY-4-34-1pc-5x3mm-Octagon-Natural-Green-PERIDOT-Free-Shipping-/400679808835?pt=Loose_Gemstones_1&hash=item5d4a60af43

 

[txgreeneyes]

This may sound like a stupid question, but please forgive me.

Did you have to take the stone out of the setting?

(I'm thinking the answer is "yes", but hoping there is a way to test without removing the stone from the mounting.)

 

[Marlow]

Please allow me to answer first.

Better would it be to measure the stone on different positions ( table facet at pavillion) - but for a quick check it is o.k.
You need a full contact of the table facet and the glass of the refractometer. If the prongs are higher it will not work.

Same with the polariscope if the setting is open. Again - it is better to check it on several position.

 

[PrecisionGem]

This may sound like a stupid question, but please forgive me.

Did you have to take the stone out of the setting?

(I'm thinking the answer is "yes", but hoping there is a way to test without removing the stone from the mounting.)

As long as the stone can sit on the table, with out the prongs touching, then you don't need to remove it from the setting. The important thing is a perfect contact with flat surface on the gem, and the glass on the refractometer.

As far as the RI liquid, you want as thin a layer as possible, you don't want the stone floating on liquid. The idea of the fluid is to make a perfect contact with the glass. This way you get the most defined shadow line. What I do is put a small drop lower than the center of the glass, then gently slide the stone onto the drop and slide it to the center of the glass. This will help to spread out and thin the RI liquid thickness, and make a good contact with the glass.

 

[needfullshinythings]

Morning folks, sorry about going missing yesterday ( wasted another day of my life supporting the national cricket team )
Thanks for answering Txgreeneyes question Marlow & PG for translating Marlows answer We all know how hard it is as a 2nd language, lots who cant use it as their given !!! ( no good at england when they was a schoolchildren )
Marlow, thanks for the link. I will certainly find something on there to play with. By the way did you do a test on your Tourmaline to see if my getting 2 green lines on the reading was correct ? TIA.