Abstract: A method of re-identifying a rough gemstone comprises providing a 3D model of a first rough gemstone; generating a series of virtual 2D silhouette images of the 3D model; processing each 2D image of the series of virtual 2D silhouette images to obtain a dataset associated with the first rough gemstone; and comparing the dataset of the first rough gemstone with an existing dataset of a rough gemstone. Where the dataset of the first rough gemstone and the existing dataset match each other, the method comprises re-identifying the first rough gemstone as the same rough gemstone from which the existing dataset was obtained.

Abstract: There is disclosed an apparatus and method for sorting gemstones from a batch of gemstones. The apparatus comprises one or more measurement locations, each comprising at least one measurement device configured to measure one or more properties of a gemstone. A continuously moveable surface supports the gemstones thereon and transports the gemstones to the one or more measurement locations. A separation device separates the gemstones from one another as they are transported on the moveable surface to the one or more measurement locations. A location trigger at a sensor location comprises a sensor for identifying when the gemstone passes through the sensor location.

Abstract: An apparatus for sorting gemstones from a batch of gemstones comprises one or more measurement locations, a conveyor comprising a plurality of discrete compartments for containing the gemstones, a delivery device configured to deliver individual gemstones from the batch of gemstones to individual compartments of the conveyor and a controller configured to synchronise a speed of the conveyor with an operation of the one or more measurement locations such that the measurements of the gemstones can be correlated with a location of the gemstones in their associated compartments. A method of sorting gemstones from a batch of gemstones is also disclosed.

Abstract: The present disclosure relates to an apparatus for measuring a color parameter of a gemstone. The apparatus comprises a support structure for supporting the gemstone at a measurement location, an illumination system for illuminating the gemstone at the measurement location, an imaging device directed towards the measurement location for obtaining an image of the gemstone, and an image processor for analyzing the image of the gemstone. The image processor is configured to identify a set of stone pixels corresponding to the gemstone in the image and identify luminance and chrominance values for each stone pixel. A color vector is calculated from an expression of the chrominance values of the stone pixels in chrominance space, the color vector extending in chrominance space from stone pixels having a relatively high luminance value to stone pixels having a relatively low luminance value. This color vector is used in the determination of the color parameter.

Abstract: A method of and an apparatus for providing an indicator for a diamond as to whether it is natural by testing for the presence or absence of one or more specific markers in the luminescence properties of the diamond, These markers are characterized by luminescence decay time and luminescence wavelength.

Abstract: A system is described for obtaining images of a gemstone, and performing quantitative analysis on the images to obtain measures of properties of the gemstone. The system comprises a support structure for supporting the gemstone at an observation position. An illumination structure is arranged to illuminate the gemstone. The illumination structure comprises a plurality of radially dispersed directional light sources directed towards the observation position, the support structure and illumination system being rotatable relative to one another around a rotation axis so that the gemstone can be illuminated by one or more of the directional light sources at each of a plurality of rotational positions, the axis of rotation being normal to a selected facet of the gemstone. An imaging device is directed towards the gemstone for obtaining images of the gemstone at each of the rotational positions, the imaging device having an imaging axis parallel to or coincident with the axis of rotation.

Abstract: A method of and an apparatus for providing an indicator for a diamond as to whether it is natural by testing for the presence or absence of one or more specific markers in the luminescence properties of the diamond. These markers are characterized by luminescence decay time and luminescence wavelength.

Abstract: Apparatus and corresponding methods for measuring a plurality of parameters of a cut gemstone while it is positioned at a single measurement location. Apparatus comprise a plurality of light sources, each configured to emit light at a different one of a plurality of emission wavelengths or ranges of wavelengths such that the emitted light illuminates at least part of the measurement location. Apparatus further comprise a sensor assembly configured to sense light at a plurality of sensing wavelengths or ranges of wavelengths for measuring the plurality of parameters. The sensed light is received at the sensor assembly from the measurement location as a result of illumination of a cut gemstone located at the measurement location.

Abstract: A method and apparatus for orientating discrete objects, such as gemstones, is described. The method comprises providing the objects on a travelling path; providing a pair of opposed walls (38) extending generally along the direction of the path; and generating relative oscillatory movement (14) between the pair of walls (38) and the travelling path (in a direction generally transverse to the direction of the path), so that the pair of walls (38) imparts lateral force to the objects to thereby urge them into their most stable orientation as they progress along the path. A device for checking the orientation of the discrete objects is also described.

Abstract: An apparatus for viewing images of a gemstone is described. The apparatus comprises a support structure for supporting the gemstone at an observation position. An illumination structure comprises a plurality of directional light sources directed towards the observation position so as to illuminate the gemstone. The support structure and illumination structure are relatively rotatable relative to one another about a rotation axis. An imaging device is arranged to obtain images of the gemstone at the observation position at a variety of relative rotational positions between the illumination structure and support structure: the imaging device has an imaging axis passing through the observation position. The support structure is arranged so that the gemstone can be placed at the observation position in such a way that the normal to a selected facet of the gemstone is within a range of tilt angles from the rotation axis.

Abstract: There is described an apparatus and method for inspecting and optionally sorting gemstones. The apparatus includes a nozzle or array of nozzles operatively connected to a vacuum pump such that a gemstone located generally underneath one of the nozzles will be supported against that nozzle by air pressure when a vacuum is applied above the nozzle. A drive system moves the nozzles along a path past a gemstone pick-up location so that a gemstone can be picked up by each nozzle as that nozzle passes the pick-up location. One or more measurement devices are located on or near the predetermined path and configured to measure at least one property of the gemstone. One or more ejection locations are provided on the path at which the vacuum applied to each nozzle is reversible to eject the gemstone from that nozzle. The apparatus may also include a plurality of dispensing bins into which the gemstones are dispensed. The bin into which each gemstone is dispensed is chosen in dependence on the measured property.

Abstract: A method and apparatus for generating a 3D model of and/or detecting inclusions in a polished gemstone such as diamond is described. The gemstone (103) is rotated in a series of discrete increments. At each rotational position of the gemstone, the gemstone (103) is illuminated with collimated light (111,112) and a silhouette image recorded. At each rotational position, the gemstone (103) is also (before further rotation) illuminated with diffuse light (109), and a diffuse image recorded. The images are analyzed to obtain a 3D model of the surface of the gemstone. Features may then be identified in the diffuse images and tracked between subsequent diffuse images. The tracked features may be located relative to the 3D model of the gemstone, taking into account reflection and refraction of light rays by the gemstone. Some or all of the located features may then be identified as inclusions.

Abstract: A system is described for obtaining images of a gemstone, and performing quantitative analysis on the images to obtain measures of properties of the gemstone. The system comprises a support structure for supporting the gemstone at an observation position. An illumination structure is arranged to illuminate the gemstone. The illumination structure comprises a plurality of radially dispersed directional light sources directed towards the observation position, the support structure and illumination system being rotatable relative to one another around a rotation axis so that the gemstone can be illuminated by one or more of the directional light sources at each of a plurality of rotational positions, the axis of rotation being normal to a selected facet of the gemstone. An imaging device is directed towards the gemstone for obtaining images of the gemstone at each of the rotational positions, the imaging device having an imaging axis parallel to or coincident with the axis of rotation.

Abstract: An apparatus for viewing images of a gemstone is described. The apparatus comprises a support structure for supporting the gemstone at an observation position. An illumination structure comprises a plurality of directional light sources directed towards the observation position so as to illuminate the gemstone. The support structure and illumination structure are relatively rotatable relative to one another about a rotation axis. An imaging device is arranged to obtain images of the gemstone at the observation position at a variety of relative rotational positions between the illumination structure and support structure: the imaging device has an imaging axis passing through the observation position. The support structure is arranged so that the gemstone can be placed at the observation position in such a way that the normal to a selected facet of the gemstone is within a range of tilt angles from the rotation axis.