The refracting prism is made of a glass with a high refractive index ( e.g. , 1.75 ) .
The refractometer is designed to be used with samples having a refractive index smaller than that of the refracting prism .
The refracting prism is made of a glass with a high refractive index ( e.g. , 1.75 ) and the refractometer is designed to be used with samples having a refractive index smaller than that of the refracting prism .