A unique collection of selective, comminuted optical glasses supplemented by purified minerals provide a reasonable range of refractive indices from 1.34 to 2.40 in increments of 0.01. This set supplements Cargille Refractive Index Liquids by explaining the types of standards available for microscopic identification by refractive index determinations.
The specimens were selected for their placement on the refractive index scale and for their accuracy and purity. As many optical glasses as possible were used, and new specimens are constantly being explored for possible inclusion as they contribute to the accuracy or completeness of the collection.
Approximately 1/2 cc of 60 different materials comminuted to -100 mesh are assembled as a set in a handsome mahogany stained wood case with tiered shelves for accessibility. Each specimen is contained in a labeled glass screw-thread vial with a plastic screwcap closure.