Our Digital Gem Refractometer is a accurate optical instrument which will give a reading of the refractive index of a clean, flat, well-polished facet to reproducibility of 0.007RI index units. This digital refractometer cover the full range from 1.30 to 2.99RI, The normal oil type refractometers range is usually 1.30 to 1.81, which have only half of the range of this New product! If you want to test gems which has higher IR above 1.81, then you have to use this digital refractometer.
It is an ideal instrument to identify the gem stones. It test the gem stones without requiring ANY messy, damaging contact oil.
RI Test Range: 1.30 to 2.99RI
Power Input: 9V Battery
Work Temperature: 25-28celsius/77-83fahrenheit
Unit Weight: Approx 750grams in box with accessories
Guarantee compare the retailing price over 800 US dollar.
No need for expensive, messy liquids that constantly need replenishing
Unit Dimensions: 160mm x 100mm x 50mm
Unit Weight: Approx 750grams/27ounces in box with accessories
Gives a reading in less than half a second.
How to Test Double Refraction Gem:
Turn the gem in the same direction through small increments, you can read the two
refractive index values of the light vibrated at right angles to each other.
Operate continuously until the gem is at 180 degree position to its initial position.
From a number of groups of measured refractive index values you can find a group
with the difference of maximum refractive index and minimum refractive index.
The difference is the value of index of double refraction of gem.
We recommend that every gem be tested two or more times, adjusting the position
slightly by shifting the stone left or right or up or down, not rotating it. Do
not move the stone too far off center. If all the readings are consistent in all positions, it is then know that the stone is well cut and a correct index is being read on the meter.
Gem Cleaning cloth
Free Standard stone sample (1.4875RI)
Free Standard stone sample (1.7552RI)
9V Battery included.
Refractometer Index Reference List (For more than 200 common gemstones, i.e. Calcite, Jadeite, Quartz etc.)
For first time use, there is a 4 step calibration which only takes 60 seconds to complete. User only needs to do the calibration once when they first use it or after being stored for a long time(months)
1: The best operational temperature is between 25-28celsius/77-83fahrenheit
2: the stone's contacting face must be polished well and have at least 3mm flat surface
3: The stone's contacting face must be very clean
4: the stone was placed well on the center of the testing plate.
Please note that the instrument's min scale is only 0.01RI. The third digits after decimal is just for reference, not correct or final reading. When the stone was moved (in different direction) to test, the stone must be sure to be placed well on the center of the testing plate. If the testing result from the screen only changes in the third digits after the decimal, the second digit is stable, it means the result is CORRECT. If when moved in different directionS, the reading from the screen changes largely(always getting lower), the first or the second digits after the decimal changes, than the stone was not placed well, or the stone's polishing face was not flat.
3 years warranty