... Index: 1.30-1.81, Size: 30x70x130mm. Gem Refractometer CL-181LLGem Tester Refractive index is one of most important ... is uniaxial or biaxial photopositive or photonegative. The gemological refractometer is characterized by small volume and less weight. It ... a popular instrument used in jewelery market.Gem refractometer CL-181LLDescription: 1)Gem refractometer, glass testing table-board,black color,c ...