Herbert Smith Gem Refractometer No.1 (c. 1903)

This early gem refractometer, designed by British mineralogist George Frederick Herbert Smith, represents one of the earliest scientific instruments created specifically for gemstone identification. Introduced in 1903, it marked a significant advancement in gemology by allowing specialists to measure a gemstone’s refractive index—a key optical property used to distinguish natural gems from imitations.

Crafted with a compact brass housing and a precision glass prism, the instrument required only a small gemstone surface to produce accurate readings. Its design set the foundation for modern refractometers still used in laboratories today.

Herbert Smith’s pioneering work—including this refractometer and his later contributions to mineral optics—helped establish gemology as a scientific discipline rather than a trade based solely on observation. This instrument stands as an important milestone in the evolution of professional gem testing.

This is a museum archives and no unit is available for sale at this moment.