Gemological Instruments

I need a refractive index/reflectivity chart
I need a refractive index/reflectivity chart Last Updated: Jun 18, 2012 06:10PM EDT Note that a refractive index and/or reflectivity chart is inclu...
Wed, 3 Sep, 2014 at 2:13 PM
Do the Presidium PRM/PRIM II require liquid or oil to operate?
Neither the Presidium Reflectivity Meter nor the Presidium Refractive Index Meter require oil as they are electronic tools.  This allows them to measure r...
Wed, 3 Sep, 2014 at 2:14 PM
How do the Presidium PRM/PRIM II handle doubly refractive stones?
Doubly refractive stones inherently have two refractive/reflective values. While optical refractometers are capable of  observing both refractive values, ...
Wed, 3 Sep, 2014 at 2:16 PM
My refractometer's manual describes a calibration block
Unfortunately the manufacturer stopped including a calibration block with their refractometers a while ago,  but did not correct their manual. We are sorr...
Wed, 3 Sep, 2014 at 2:16 PM
Can a refractometer be used on mounted stones?
Refractometers are best used with loose stones. If testing mounted stones, make sure that the facet of the stone is  flat on the testing surface and is fr...
Wed, 3 Sep, 2014 at 2:17 PM
Are batteries included with the refractometer? Where?
Yes, batteries are included with every gemological refractometer we sell. They should be located in the top flap of  the soft case pouch that comes with t...
Wed, 3 Sep, 2014 at 2:17 PM