System and method for evaluating and determining color in gemstones

A method for comparing a stone under test (SUT) to a plurality of saved SUT data, the method comprising:

• providing an enclosure, the enclosure including a stage for mounting the SUT, the stage comprising a stage rotation axis, the stage being rotatable about the stage rotation axis by a rotation device;
• capturing, by one or more provided image sensors, a first plurality of SUT images at different positions about the stage rotation axis and a sensor elevation axis;
• illuminating the SUT with:
• one or more broadband visible (BBV) light sources stationary with respect to the one or more image sensors;
• and
• one or more ultraviolet (UV) light sources configured to move with the one or more image sensors;
• capturing, by the one or more image sensors, a color indicative plurality of images at different positions about the stage rotation axis and the sensor elevation axis while illuminating the SUT from different angles or elevations;
• characterized in that:
• the one or more image sensors are mounted on a movable arm, the arm being rotatable around the sensor elevation axis at a variety of angles to capture images of a mounted SUT, the sensor elevation axis being normal to the stage rotation axis;
• the one or more UV light sources being mounted on the arm in the vicinity of the one or more image sensors;
• generating, by a programmable controller,
• (i) an SUT 3D volumetric model of the SUT from the first plurality of images,
• (ii) an SUT color measurement based on the 3D volumetric model and the color indicative plurality of images, and
• (iii) SUT data based on the SUT 3D volumetric model and the SUT color measurement;
• and
• comparing, by the programable controller, the SUT data to the plurality of saved SUT data of one or more stones;
• and
• generating a match, by the programable controller, between the SUT and a specific stone of the one or more stones when a predefined matching criterion occurs between the SUT data comprising the SUT 3D volumetric model and the SUT color data and the plurality of saved SUT data comprising the SUT 3D volumetric model and the SUT color data of the specific stone of the one or more stones.