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DK91006-300 High Quality Refractometer with interior scale

DK91006-300 High Quality Refractometer with interior scale


Introducing the DK91006-300 High Quality Refractometer, a precision instrument for measuring refractive index with unparalleled accuracy. With a measuring range from 1.30 to 1.81 RI and a minimum gradation of 0.01RI, this refractometer provides precise readings for your gemstone and jewelry needs.


Equipped with internal LED illumination and a polarizing filter, this refractometer ensures optimal visibility and accuracy in every measurement. The momentary switch allows for easy control of the illumination, enhancing usability and convenience.


Compact and portable, with dimensions of 35mm x 63mm x 115mm, each refractometer comes in a lockable case for secure storage and transport. Please note that RI Liquid is not included for air shipping orders.


Experience precision and reliability with the DK91006-300 High Quality Refractometer, your essential tool for gemstone analysis and quality assurance.




Measuring range: 1.30 – 1.81 RI

Minimum gradation: 0.01RI

Illumination: internal LED illumination with momentary switch

Scale division: 0.01nD

Size: 35mm x 63mm x 115 mm

Filter: polarizing filter

Each one in a lockable case

RI Liquid is not included for all air shipping orders. You will need to purchase locally. 


How to Use a Refractometer Effectively


Step 1: Set Up the Instrument

Place the refractometer on a stable worktable and open the upper cover. Using a thin glass bar, carefully apply a few drops of the specialized refractive oil onto the prism's surface.


Step 2: Prepare the Gem

Position the gem to be measured so that its ground surface is in close contact with the prism. Gently press it down to ensure even distribution of the refractive oil between the two surfaces. Close the upper cover securely.


Step 3: Optimize Viewing Conditions

Align the entrance filter of the refractometer with the light source to create uniform illumination. Adjust the brightness of the viewing field to ensure consistent luminance.


Step 4: Achieve Sharp Focus

Fine-tune the focus until the scale becomes as sharp as possible, enabling accurate measurements.


Step 5: Place the Gemstone

Gently slide the gemstone from the metal surround onto the prism. Make sure the chosen facet is facing down and rests on the prism's surface.


Step 6: Rotate and Observe

Peering through the eyepiece, gradually rotate the gemstone through a full 360-degree rotation while maintaining constant contact between the chosen facet and the prism.


Step 7: Record Measurements


a. Single Shadow Edge: If only one shadow edge is observed, note the exact position of the shadow edge. Record this reading with decimal precision.


b. Double Shadow Edges: If two shadow edges are visible, record the highest reading with three decimal places. Then, rotate the gemstone and record the lowest reading.


By following these refined steps, you will ensure accurate and reliable measurements using the refractometer. Remember to handle both the instrument and the gemstone with care throughout the process.

DK91006-300 High Quality Refractometer with interior scale

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