Feature 1Quick Identification: The refractometer can quickly and accurately identify a variety of single and double gemstones, helping to identify diamonds, moissanite, etc. 2Strong Practicality: The primary use of the portable gemstones refractometer is to measure the angle at which light is bent or refracted through the stone. 3Specially Designed: This refractometer is specially designed to measure the refractive index of gemstones and materials. 4High Accuracy: Professional gemstones refractometer has high accuracy, small size, easy portability and easy operation. 5Clear Display: The jewelry gemstones refractometer has a clearly visible display for easy reading.Item Type: Portable Gemstones RefractometerMaterial: Glass, ABSProduct size:Approx. 128 x 60 x 32mm / 5.0 x 2.4 x 1.3inMeasuring Range: 1.30 to 1.81Minimum Division Value: 0.01Liquid: Refractive Oil (Shipped with Liquid)Flashlight Battery: 1 x 1.5V AA Battery (Shipped Without Battery)Weight: Approx. 590g / 20.8oz .wang-edit-text{ font-family:'Arial' !important; } .wang-edit-text table { border-top: 1px solid #000; border-left: 1px solid #000; } .wang-edit-text table td, .wang-edit-text table th { border-bottom: 1px solid #000; border-right: 1px solid #000; padding: 3px 5px; } .wang-edit-text table th { text-align: center; }Package List1 x PortableGemstonesRefractometer1 x Flashlight1 x Refractive Oil1 x Box1 x User ManualNote1.The refractive index of gemstones is a very important optical parameter. The gloss of the gemstones can be determined by this parameter. Since different gemstones have a fixed refractive index, all kinds of gems can be determined according to the refractive index. Birefringence can also be measured. This parameter can be used to determine whether a gemstones is uniaxial or biaxial.2.Shipped with liquid, shipped without battery.