The invention provides a method of automating the classification of a diamond gemstone. An infra-red absorption spectrum of the gemstone is provided. Features corresponding to absorption by water and intrinsic absorption by a diamond lattice are subtracted from the absorption spectrum. The spectrum is analysed to identify predetermined absorption features corresponding to lattice defects in the diamond. The gemstone is classified according to the intensities of the predetermined absorption features. The results of the classification are saved in a database.
G01N 21/35 - Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
A sorting apparatus (100) for classifying candidate rough gemstones in aggregate material, the apparatus comprising: a transport system (102) for individually transporting a stone from the aggregate material to at least one measurement location; a measurement system (104) configured to determine, at the at least one measurement location, one or more of: whether the stone comprises diamond material, whether the stone comprises boart, and the shape of the stone; the apparatus further comprising a dispenser system (106) configured to dispense the stone from the transport system to one of a plurality of locations in dependence on the determination of the measuring system.
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.
There is described a method for calibrating or cross calibrating one or more measuring instruments by providing a sample of three or more objects to be measured to which target statistics for one or more material properties has been assigned wherein said target statistics are independent of the order of presentation of individual objects, providing observed statistics for the sample of three or more of said objects wherein the observed data set is recorded from the measuring device and wherein said observed statistics are independent of the order of presentation of individual objects and transforming the actual measurement output of the measuring device so that the transformed observed statistics match the target statistics.
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.
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. An image processor is provided for identifying sparkle regions in the images corresponding to reflections from individual light sources by individual facets and providing a quantitative measure of the gemstone on the basis of properties of the sparkle regions.
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 analysed 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.
An apparatus and method for aligning a gemstone such as diamond (106) with a predetermined vertical axis (108) is described. The apparatus includes an upwardly extending nozzle (105) aligned with the vertical axis (108) and sized to allow the gemstone (106) to settle into it under the action of gravity so that the article is supported by the aperture. A fluid supply system supplies fluid to the nozzle (105) under sufficient pressure to support the article within or above the aperture. A fluid pressure control system controls the pressure of fluid supplied to the nozzle (105), so that it can be reduced gradually.
B24B 9/16 - Machines or devices designed for grinding edges or bevels on work or for removing burrsAccessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain of diamonds, of jewels or the likeDiamond grinders' dopsDop holders or tongs
B28D 5/00 - Fine working of gems, jewels, crystals, e.g. of semiconductor materialApparatus therefor
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. The arrangement of directional light sources is such that, for any tilt angle within the range, at least one of the directional light sources will be specularly reflected from the selected facet into the imaging device for at least one rotational position of the support structure.
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