Provided is a gemstone treated with a cut expressing a reflected image pattern not recognized before, wherein the gemstone includes the crown 100 having the table 110 and plural bezel facets 130, and the pavilion 200 having the culet 210 and plural main facets 220; the girdle 300 is formed between the crown 100 and the pavilion 200; a direction of a horizontal component of an inclination direction of the bezel facet 130 from the table 110 to the girdle 300 is set to be different from a direction of a horizontal component of an inclination direction of the main facet 220 from the culet 210 to the girdle 300; and inclination angles of the bezel facet 130 and the main facet 220 are set so that a light that enters the table 110 is reflected by two of the main facets 220 and emitted from the bezel facet 130.

A round stone is intended for being inserted contiguously with other similar stones to as to conceal the setting of the stones. Facets are bevel-formed between the girdle and the pavilion. Grooves, open at the two ends thereof, are formed, as by sawing in a plane perpendicular to the axis, in the facets to receive the setting claws.

The invention relates to a method and an apparatus for manufacturing a workpiece, specifically a rough diamond, into a product, specifically a brilliant. The method is performed by an apparatus providing a laser beam coupled into a pressurized fluid jet. The method comprises executing multiple cuts of the workpiece with the laser beam according to a predetermined cut-sequence to remove workpiece material with each completed cut. The method further comprises executing multiple rotations of the workpiece around the same axis of revolution according to a predetermined rotation-sequence. Thereby, a rotation is executed after a completed cut, and for executing a cut the laser beam is moved along a two-dimensional path.

Methods, apparatus, and systems for managing optical characteristics of gemstones with diffractive structures are provided. In one aspect, a method includes obtaining a three-dimensional model of a gemstone including representations of surfaces of the gemstone, identifying a region on a surface of the gemstone having an optical value higher than one or more other regions on the surface of the gemstone by analyzing the three-dimensional model of the gemstone, and determining a diffractive structure to be arranged on the identified region of the surface of the gemstone, such that the gemstone with the diffractive structure has a higher optical performance than the gemstone without the diffractive structure. The method can also include fabricating the determined diffractive structure on the identified region of the surface of the gemstone.

The invention is directed to shallow pavilion, cut diamonds having excellent optical characteristics. The pavilion surface includes a plurality of substantially planar main pavilion facets, each of which extend from the girdle to a pointed culet defining the bottom most portion of the cut diamond. The crown angle is in the range of between about 29 degrees to about 36 degrees, and the pavilion angle is in the range of between about 15 degrees and about 34.5 degrees. The shallow pavilion, cut diamonds of the invention may be either round shaped cut diamonds or fancy shaped cut diamonds.

A gemstone includes a crown, a pavilion, and a girdle disposed between the crown and the pavilion. The girdle has an octagon-shaped cross-section. The surface of the gemstone is generally divided into a number of groups of interlocking facets disposed at a variety of angles. The groups of facets comprising the surface of the crown generally include star facets, upper intermediate crown facets, lower intermediate crown facets, main crown facets, and upper girdle facets. The upper girdle facets generally abut an upper edge of the girdle. The groups of facets comprising the surface of the pavilion include culet-adjacent facets, candle facets, main pavilion facets, and lower girdle facets. The lower girdle facets generally abut a lower edge of the girdle.

A gemstone includes: a table defining an area; and a scanable indicia formed in the gemstone at least partially positioned within an orthographic projection of the area extending along an axis, the axis extending perpendicularly through the table.

A decorative structure (20) comprising a planar support (22) and a faceted microstructure (24) on at least one side of the planar support (22) is provided. The decorative structure (20) may further comprise an at least partially reflective layer (26) configured to at least partially reflect light that passes through the microstructure (24). The faceted microstructure (24) comprises a plurality of grooves (28) creating a pattern of facets (30) over the surface of the support (22), such that the microstructure (24) is capable of splitting incident light into spectral colours. In embodiments, the grooves (28) have a triangular or V-shaped profile. Methods of making a decorative structure(20) and articles incorporating the decorative structure (20) are also described.

Methods, apparatus, and systems for fabricating diffractive structures on gemstones for high optical performance are provided. In one aspect, a method includes obtaining a plurality of gemstone characteristics of a gemstone, determining that the gemstone exhibits each of the plurality of gemstone characteristics within a respective predetermined range, identifying a diffractive structure setting associated with a combination of the respective predetermined ranges for the plurality of gemstone characteristics, and fabricating diffractive structures on the gemstone according to the diffractive structure setting.