A process of assigning a colour grade to a diamond, including the steps of (i) determining the N3 and C-center content of a diamond (110); (ii) comparing the N3 and C-center content of the diamond with a previously acquired data set from a plurality of diamonds each having a colour grading previously assigned thereto, and (iii) assigning a colour grade to the diamond upon a correlation of the N3 and C-center content of said diamond with a grade of said previously acquired data set; wherein said previously acquired data set comprises a correlation between N3 and C center content and optical absorbance in the visible light spectrum for each diamond of said plurality of diamonds.

A method of analysing an at least partially transparent object, such as a gemstone, includes fixing the object in a holder; immersing the object in the holder in an immersion material; and analysing internal and/or external features of the object. Analysing comprises visualizing an internal and/or external portion of the object using light rays while the object is immersed in the immersion material, and determining characteristics of the object based on the visualized internal and/or external portion of the object. During the analysing step, the difference between the refractive index (RI) of the immersion material and the RI of at least an immersed portion of the holder, which is in contact with the object, is less than 0.3.

Systems and methods here may be configured for cooling and examining materials. In some example embodiments, the system may include a main thermoconductive body with indentations on the top surface, a bottom surface having legs structures along the edge, wherein the bottom surface and the plurality of leg structures form a partially enclosed bottom chamber, and a center channel connecting the top surface and the bottom chamber.

The application provides a gemstone testing apparatus for testing a specimen. The gemstone testing apparatus includes a handheld casing, a plurality of light sources, a test probe, a photodetector, a processor unit, and a display unit. The test probe is placed at one end of the handheld casing. A first end of the test probe is placed outside the handheld casing. The plurality of light sources is provided for emitting light rays towards an area that is in the vicinity of the first end. The first end is adapted for receiving light rays from the specimen and for transmitting the light rays to a second end of the test probe. The photodetector is arranged to measure an intensity of the light rays from the second end. The processor unit is provided for determining a material of the specimen in accordance to a measurement of the intensity of the light rays.

Systems and methods of quantum sensing include depositing a sample volume onto an ensemble of quantum defects, hyperpolarizing spins in the sample volume, performing a sensing sequence, and reading out information regarding electronic spin states of the quantum defects in the ensemble of quantum defects, which sense the hyperpolarized spins in the sample volume.

Systems and methods here may be configured for cooling and examining materials. In some example embodiments, the system may include a main thermoconductive body with indentations on the top surface, a bottom surface having legs structures along the edge, wherein the bottom surface and the plurality of leg structures form a partially enclosed bottom chamber, and a center channel connecting the top surface and the bottom chamber.

Methods and systems are provided for facilitating comparison of gemstones having multiple attributes that characterize the gemstones. A facilitated comparison system receives from a user a selection of a gemstone in a collection of the gemstones. Each gemstone in the collection is associated with a selling index indicating a probability of the gemstone being bought by a customer. For each of a predetermined set of the attributes, the system determines one or more comparable ranges. The system identifies alternate gemstones to recommend using the comparable ranges for the attributes and the selling indices of the gemstones. The system displays to the user the selected gemstone and one or more of the alternate gemstones for comparison.

Gemstone grading method including illuminating the gemstone by light having a plurality of spectral components, each modulated according to a spectrally specific modulation (e.g., of intensity, frequency, phase), collecting the light following interaction with the gemstone, extracting from the collected light a set of intensity values for a respective set of modulation parameter values to provide a transmittance spectrum, and an output indicative of the transmittance spectrum (e.g., color, clarity, fluorescence grade). A complementary system includes a plurality of monochromatic light sources and respective modulators for simultaneously illuminating a gemstone with a modulation spectrally specific for each light source, a detection system for collecting the light following interaction whose signals are fed via a communication system to a data processor configured to extract a set of intensity values for a respective set of modulation parameter values to provide a transmittance spectrum and an output indicative thereof.

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.

Provided herein is an apparatus for assessing a fluorescence characteristic of a gemstone. The apparatus comprises an optically opaque platform for supporting a gemstone to be assessed, one or more light source to provide uniform UV and non-UV illumination, an image capturing component, and a telecentric lens positioned to provide fluorescent images of the illuminated gemstone to the image capturing component. Also provided are methods of fluorescence analysis based on images collected using such an apparatus.