Gemological Tools Refactrometer

The Fable Gemological Refractometer is a high-precision, portable instrument designed for the rapid identification of precious and semi-precious stones. It features a high-hardness synthetic Cubic Zirconia (CZ) test prism and a built-in monochromatic LED light source (589nm) that provides a sharp, clear shadow line for accurate readings.

Quick Start Guide: How to Use
Using a refractometer requires care to avoid scratching the delicate testing prism. Follow these steps:
1. Preparation
• Clean the Stone: Use a lint-free cloth to ensure the gemstone is completely free of dust, oils, or fingerprints.
• Clean the Prism: Gently wipe the metal table and the glass prism with a soft cloth.
2. Applying the RI Liquid
• Place a tiny drop of Refractive Index (RI) liquid (usually 1.78 or 1.81) onto the center of the prism.
• Tip: Use just enough to create a thin film; too much liquid will make the stone "float" and give an inaccurate reading.
3. Positioning the Stone
• Place the largest flat facet of the gemstone (the table) onto the liquid drop.
• Gently slide the stone to the center of the prism to ensure a good optical seal.
• Close the light-shielding cover to block out ambient light.
4. Taking the Reading
• Turn on the built-in light source.
• Look through the eyepiece. You will see a vertical scale with a dark shadow crossing it.
• The Reading: The point where the shadow meets the light area on the scale is the Refractive Index.
• Birefringence Test: Rotate the stone 90^\circ or 180^\circ on the prism. If the shadow line moves or splits into two lines, the stone is doubly refractive (like Ruby or Sapphire).
5. Cleanup (Crucial)
• After testing, immediately remove the stone.
• Wipe the prism and the stone with a soft tissue dampened with a small amount of alcohol or water to remove the RI liquid, as the chemicals in the liquid can damage the prism if left for too long.