Abstract: Disclosed are methods and devices for assessing the colors of diamonds. In embodiments, the color of finished diamonds cut from a given rough diamond is assessed by analyzing the effect on light interacting with the rough diamond to give a reasonable (that is to say commercially significant) assessment of the color quality of the finished diamond.

Abstract: Methods and apparatus for real-time dynamic analysis of a chemical etching process are provided. The apparatus comprises an optical element (36) operative to pass a beam of electromagnetic radiation at least at two points in time through a liquid phase (42) comprising at least one chemical component and including an etchant, wherein the etchant is operative to etch a solid. A detector (60) is operative to perform an ex-situ non-contact scanning detection of the electromagnetic radiation subsequent to passing through the liquid phase in a near infra-red range (700-2500 nm) at the at least at two points in time so as to detect a change in an optical property of at least one of the at least one chemical component and the etchant.