Gemology Online 2014 Faceting Design Competition!
Welcome to the GemologyOnline.com Forum
A non-profit Forum for the exchange of gemological ideas
It is currently Mon Jul 28, 2014 12:12 am

All times are UTC - 4 hours




Post new topic Reply to topic  [ 9 posts ] 
Author Message
 Post subject: Digital Gem Refractometer
PostPosted: Fri Jul 27, 2007 2:39 pm 
Offline
Established Member
User avatar

Joined: Wed Mar 28, 2007 12:35 am
Posts: 44
Location: Nepal
Hi Doos ,
I saw a gemological digital refractometer on ebay.

Do you have any idea about its accuracy,reliablity and mantainance.Hope Dr.Hanneman may have some remarks on this item. :lol:

_________________
Sarraf Gems.
www.researchut.com/gems


Share on FacebookShare on Twitter
Top
 Profile  
 
 Post subject:
PostPosted: Sat Jul 28, 2007 6:32 am 
Offline
Platinum Member

Joined: Sun Oct 16, 2005 12:42 pm
Posts: 2591
Hi,

This seems to be a jemeter/gemmeter type instrument.
I don't own one, but some here who do find it very useful.

Looking at the images, it says to come from "gem instruments" which is the GIA, but I doubt it is. So propably a cheap knock-off of the jemeter ... or a great cheaper alternative.
Hard to tell.


Share on FacebookShare on Twitter
Top
 Profile  
 
 Post subject:
PostPosted: Sat Jul 28, 2007 2:06 pm 
Offline
Platinum Member
User avatar

Joined: Tue Jan 02, 2007 8:20 pm
Posts: 2390
They call it a refractometer but it is a reflectometer. It can read percent reflectivity or converted refractive index which isn't a bad idea.
It does say Gem Instruments which is a trademark of GIA and when they notice it these people will not be able to sell on ebay until they remove the infringing label.

I think it is still too expensive.

One of our members recently allowed me to examine his Presidium reflectivity meter. They are nicely made and do the same thing for less than $200 end user. They read out in (very) arbitrary units and you calibrate with known stones and compare to a chart which comes with the unit.

I also had occasion to chat with another list member who has the $800 Austrian made "Gemmeter" which has the clever birefringence chart built in.
He hates it. He says it takes 45 minutes of calibration every time he uses it
which defeats the purpose for which he bought it, namely portable quick and easy readings.


Last edited by G4Lab on Sat Jul 28, 2007 8:46 pm, edited 1 time in total.

Share on FacebookShare on Twitter
Top
 Profile  
 
 Post subject:
PostPosted: Sat Jul 28, 2007 4:42 pm 
Offline
Moderator

Joined: Sun Oct 16, 2005 12:42 pm
Posts: 2850
Location: Ho Chi Minh City, Vietnam
Have I mentioned how glad that I am to not have bought a Gemmeter after that comment? :)


Share on FacebookShare on Twitter
Top
 Profile  
 
 Post subject:
PostPosted: Sat Jul 28, 2007 8:48 pm 
Offline
Established Member
User avatar

Joined: Wed Mar 28, 2007 12:35 am
Posts: 44
Location: Nepal
Thank to everybody for your comments on this product.I was quite confused whether it is similar with the product discussed on the research topic past Feb this year as "Digital Refractometer - Soliciting Input"
Its link is http://gemologyonline.com/Forum/phpBB2/ ... php?t=2098

_________________
Sarraf Gems.
www.researchut.com/gems


Share on FacebookShare on Twitter
Top
 Profile  
 
 Post subject:
PostPosted: Sun Jul 29, 2007 12:59 am 
Offline
Gemology Online Veteran

Joined: Mon May 14, 2007 11:00 am
Posts: 826
Location: Monterey, CA
rishi,

Regarding your questions:

With a tolerance of 0.007, you can forget about determining birefringence or even if the stone is singly or doubly refractive.

If it utilizes infrared light, you can forget about getting accurate RI values for highly dispersive stones. Sure, you can "calibrate" it to have diamond read 2.417, but then you will never be able to get strontium titanate to read 2.41.

If you want to identify unknowns with RI below 1.8, get a critical angle refractometer. However if you just want to identify the common diamond simulants, get yourself a "Diamond Eye" which only costs $89.

If your goal is to buy an instrument which will save you time and identify unknowns without requiring any knowledge or effort on your part, save your money and pray for a miracle.


Share on FacebookShare on Twitter
Top
 Profile  
 
 Post subject:
PostPosted: Sun Jul 29, 2007 12:06 pm 
Offline
Established Member
User avatar

Joined: Wed Mar 28, 2007 12:35 am
Posts: 44
Location: Nepal
Thank you Dr. Hanneman , I was supposed to purchase it but after reading your views on this item i have decided not to buy it. :smt116

_________________
Sarraf Gems.
www.researchut.com/gems


Share on FacebookShare on Twitter
Top
 Profile  
 
 Post subject:
PostPosted: Mon Jul 30, 2007 2:00 am 
Offline
Valued Contributor
User avatar

Joined: Sat Jun 02, 2007 8:03 pm
Posts: 179
Location: N. Idaho
I would be greatful to know where one can purchase a Diamond Eye for $89.00

Thanks.


Share on FacebookShare on Twitter
Top
 Profile  
 
 Post subject:
PostPosted: Mon Jul 30, 2007 2:28 am 
Offline
Platinum Member
User avatar

Joined: Tue Jan 02, 2007 8:20 pm
Posts: 2390
Directly from Dr. Hanneman of course.


Share on FacebookShare on Twitter
Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 9 posts ] 

All times are UTC - 4 hours


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Gemology Style ported to phpBB3 by Christian Bullock