A system comprises a faceted structure imaging assembly and a faceted structure image analyzer. The system is configured to determine carat weight of a gemstone while in a mounted setting. In a first mode, the imaging assembly obtains a first image of a top gemstone surface. The image analyzer uses the first image to obtain at least one gemstone dimension, such as table and diameter dimensions. In a second mode, the imaging assembly obtains a second image of the top gemstone surface while a colored light pattern is reflected onto the gemstone. The image analyzer uses the second image to obtain at least one other gemstone dimension, such as crown and pavilion angles. The image analyzer uses the dimensions obtained from the first and second images to determine weight information of the gemstone. The system quickly determines gemstone weight reliably and consistently without skilled gemologists or removal from the setting.

A method for generating a highly distinctive signature of a certain diamond, the method may include generating, based on one or more images of the certain diamond, a certain diamond signature of the certain diamond; finding, out of a group of reference diamonds, other diamonds having other diamond signatures; wherein the finding comprises calculating similarities between the certain diamond signature and reference diamond signatures of the reference diamonds of the group; and generating a new certain diamond signature that significantly differs from signatures of the other diamonds.

A method for generating a highly distinctive signature of a certain diamond, the method may include generating, based on one or more images of the certain diamond, a certain diamond signature of the certain diamond; finding, out of a group of reference diamonds, other diamonds having other diamond signatures; wherein the finding comprises calculating similarities between the certain diamond signature and reference diamond signatures of the reference diamonds of the group; and generating a new certain diamond signature that significantly differs from signatures of the other diamonds.

There is provided a computerized system and method of generating a unique identification associated with a gemstone, usable for unique identification of the gemstone. The method comprises: obtaining one or more images of the gemstone, the one or more images captured at one or more viewing angles relative to the gemstone and to a light pattern, thus giving rise to a representative group of images; processing the representative group of images to generate a set of rotation-invariant values informative of rotational cross-correlation relationship characterizing the images in the representative group; and using the generated set of rotation-invariant values to generate a unique identification associated with the gemstone. The unique identification associated with the gemstone can be further compared with an independently generated unique identification associated with the gemstone in question, or with a class-indicative unique identification.

There is provided a computerized system and method of generating a unique identification associated with a gemstone, usable for unique identification of the gemstone. The method comprises: obtaining one or more images of the gemstone, the one or more images captured at one or more viewing angles relative to the gemstone and to a light pattern, thus giving rise to a representative group of images; processing the representative group of images to generate a set of rotation-invariant values informative of rotational cross-correlation relationship characterizing the images in the representative group; and using the generated set of rotation-invariant values to generate a unique identification associated with the gemstone. The unique identification associated with the gemstone can be further compared with an independently generated unique identification associated with the gemstone in question, or with a class-indicative unique identification.

Systems and methods for evaluating gemstones are disclosed. The system includes a gemstone holding case, an illumination pad and an image capturing and gemstone evaluation device. The case includes a transparent viewing window in a top wall, a translucent bottom wall and a compressible light-diffusing pad for receiving gemstones thereon. The case and pad are dimensioned such that, when closed, the viewing window presses the gemstones into the pad holding them in place and level and allowing for in situ gem imaging. The illumination pad includes embedded LEDs for selectively illuminating the portion of the pad on which the case is placed. The controllable lighting, translucent case and diffusive pad serves to evenly light the gems and reduce unwanted light thereby improving the images and analysis performed using the image capturing and gemstone evaluation device. Methods for analyzing gemstones under diffuse lighting using the system is also disclosed.

Systems and methods for evaluating gemstones are disclosed. The system includes a gemstone holding case, an illumination pad and an image capturing and gemstone evaluation device. The case includes a transparent viewing window in a top wall, a translucent bottom wall and a compressible light-diffusing pad for receiving gemstones thereon. The case and pad are dimensioned such that, when closed, the viewing window presses the gemstones into the pad holding them in place and level and allowing for in situ gem imaging. The illumination pad includes embedded LEDs for selectively illuminating the portion of the pad on which the case is placed. The controllable lighting, translucent case and diffusive pad serves to evenly light the gems and reduce unwanted light thereby improving the images and analysis performed using the image capturing and gemstone evaluation device. Methods for analyzing gemstones under diffuse lighting using the system is also disclosed.

A fast method for batch screening diamonds includes placing diamonds on a worktable, turning on a light source arranged on one side of the worktable to shed light on the diamonds where the light includes visible light, photographing the diamonds on the worktable through an imager to obtain a basal image showing the distribution of the diamonds, switching the light source to shortwave UV light with a wavelength ranging from 180 nm to 250 nm, maintaining the light source in work condition for a period of time and then turn it off, photographing the diamonds on the worktable through the imager to obtain a phosphorescence distribution image showing phosphorescent diamonds, overlapping the basal image with the phosphorescence distribution image to obtain a phosphorescence comparison map, marking the phosphorescent diamonds on the phosphorescence comparison map through image recognition technology, and then picking out the phosphorescent diamonds as suspicious diamonds.

A fast method for batch screening diamonds includes placing diamonds on a worktable, turning on a light source arranged on one side of the worktable to shed light on the diamonds where the light includes visible light, photographing the diamonds on the worktable through an imager to obtain a basal image showing the distribution of the diamonds, switching the light source to shortwave UV light with a wavelength ranging from 180 nm to 250 nm, maintaining the light source in work condition for a period of time and then turn it off, photographing the diamonds on the worktable through the imager to obtain a phosphorescence distribution image showing phosphorescent diamonds, overlapping the basal image with the phosphorescence distribution image to obtain a phosphorescence comparison map, marking the phosphorescent diamonds on the phosphorescence comparison map through image recognition technology, and then picking out the phosphorescent diamonds as suspicious diamonds.

A method of characterising a composition of a gemstone comprises irradiating an upper portion and a lower portion of the gemstone with one or more pulses of ultraviolet radiation at a wavelength of substantially 225 nm or less; capturing luminescence emitted by the upper portion of the gemstone and luminescence emitted by the lower portion of the gemstone in one or more time windows having a predetermined relationship with the or each pulse; and comparing properties of the captured luminescence from the upper and lower portions. A composition of the gemstone is characterised, based upon the comparison.