De Beers UK Ltd

Gersan Establishment

De Beers Centenary Ag

Martin Cooper

James Gordon Charters Smith

Michael Peter Gaukroger

Peter Stanley Rose

David Fisher

Graham Ralph Powell

Colin McGuinness

Paul D Priestman

Keith Barry Guy

David Hamilton

Andrew John Portsmouth

Maxwell Ralph Willis

Sarah Louise Foster

Siobhan Margaret D'Gama

Andrew David Garry Stewart

Jonathan G Kendall

Maxwell R Willis

Timothy Howard Leaton

Christopher Daws

Philip Read

Colin Mcguinness

Michael John Crowder

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.

Apparatus for sorting gemstones

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.

Luminescence measurements in diamond

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.

Gemstone sparkle analysis

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.

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.

Gemstone viewer

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.

Gemstone inspection

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 () is rotated in a series of discrete increments. At each rotational position of the gemstone, the gemstone () is illuminated with collimated light () and a silhouette image recorded. At each rotational position, the gemstone () is also (before further rotation) illuminated with diffuse light (), 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.

Inclusion detection in polished gemstones

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 porperties of the sparkle regions.

An information mark invisible to the naked eye is applied to the polished facet of a diamond gemstone by coating the diamond gemstone surface with an electrically conductive layer so as to prevent the diamond becoming charged, forming the mark with a focused ion beam, and cleaning the diamond surface with a powerful oxidizing agent to reveal a mark having an appropriate depth, which does not detrimentally affect the clarity or color grade of the diamond.

Diamond marking

An invisible information mark is provided on a facet of a diamond gemstone by applying a plasma resist to the exposed surface of the gemstone, applying an electrically conducting layer of metal to the region where the information mark is to be formed, ablating a selected zone of the metal and resist layers by ultraviolet laser thus forming a mask on the surface of the facet, electrically connecting the metal layer and plasma etching the facet through the mask, thus forming a mark of appropriate depth on the surface of the gemstone.

Marking diamond

In order to produce on the table of a diamond gemstone (,), an information mark which is invisible to the naked eye using a &times;10 loupe, an ultraviolet laser (,) having a wavelength of 193 nm is used in association with a mask (,) to irradiate the surface of the stone (,) at a fluence of less than 2 J/cm,per pulse and with not fewer than 100 pulses, in the presence of air which reacts with the diamond (,) and causes the mark to be formed without any darkening which is visible when viewing using a microscope.

Growing community of inventors

Buckinghamshire, United Kingdom

James Gordon Charters Smith