Disclosed herein, according to an aspect of some embodiments, is a dipping refractometer. The dipping refractometer includes a prism and a casing, housing a light source and a light sensor. The prism is mounted in/on the casing such as to allow dipping the prism in a fluid such that two surfaces of the prism and the fluid forming two respective direct prism-fluid interfaces. The prism, the light source, and the light sensor are configured such that for a continuous range of values of fluid refractive indices, most of the light incident on the light sensor, originating from the light source, undergoes total internal reflection off of each of the two direct prism-fluid interfaces.