Gemological Gemstone Gem Refractometer Built-in Light

The Gemological refractometer is considered by many to be the most important of all gem testing instruments. The primary use of the refractometer is to measure the angle at which light traveling through the stone is bent or refracted. This is called Refractive Index (R.I.). As Refractive Index is usually different for different gemstones, this provides an important clue for accurate gemstone identification. Gemological refractometer also can be used to determine whether or not a stone is single or double refracting. For doubly refracting stone, based on the difference between 2 readings you obtain from the refractometer, strength of the gemstone's double refraction (birefringence) may be computed and it offers an important gem identification aid, as it differs from gem to gem. Also refractometer is one of the few instruments capable to give you information for opaque stones as well as transparent stones. Quality of the instrument is important to enable you to perform consistent and reliable test for years to come. Our refractometer has all metal construction with built-in light (no flashlight or any other light source required) and polarizing filter, allowing you to perform all needed tests, it comes with vinyl soft case with belt loop for convenience while traveling and hard case for safe storage. Features: All metal quality construction Built-in LED light source with 3 x 1.5v batteries - included Accuracy: 0.01 Measurement range: 1.30 - 1.81 Polarizing Filter Weight: 0.9 lb Application: Gemology Hard and soft cases are included R.I. liquid is not included, please purchase certified R.I. oil from reputable sources. Please be aware that R.I. liquid is not included.