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H Edit 16 terms found

H
A grade in GIA’s Color Grading System…. in the middle of the “Near Colorless” category.
Hacking
Introduced around 1972, this feature causes the second hand to ‘stop dead’ when the winding crown is pulled out fully to set the time, thus allowing for more easily synchronizing of one or more watches.
Hairspring
See Balance Spring.
Hallmark
A mark or stamp indicating the purity of a metal, or the date and/or country of import.
Hardness
The resistance of a substance to being scratched. Mohs scale of relative hardness consists of 10 minerals, each scratching all those below it in scale and being scratched by all those above it. Diamond is 10 on the Mohs scale of hardness, meaning that the only thing that can scratch a diamond is another diamond. Tests prove that diamond is approximately five to 150 times as hard as corundum, the next hardest mineral.
Harry Winston
A famous Beverley Hills jeweler who is known as the “Jeweler to the Stars”. There are now many Harry Winston store around the world.
Head
The metal basket which holds the diamond in place with prongs. The head is attached to the ring, earrings, pendant, etc.
Heart Shaped Diamond
A fancy diamond cut, which is cut to resemble the popular Valentine’s Day heart shape. It is a modified brilliant cut with a heart-shaped girdle outline that is similar to the Pear Shape Diamond, except that there is a cleft at the top. In fact, often the reason diamond cutters may choose a Heart Shape over a Pear Shape may be that the rough diamond contained an inclusion located in the cleft. The skill of the cutter can make a great difference in the beauty of this cut.
Hearts & Arrows
A Round Brilliant Cut diamond that is cut and polished to ideal proportions with exceptional symmetry and polish which shows eight heart shapes (Pavilion view) and eight arrows (Crown view) when observed through a special viewer called a FireScope. There is no industry standard of diamond proportions.
Heat Treatment
The application of high heat to a gemstone in order to improve its color and clarity.
Hermetic
Completely sealed, expecially against the escape or entry of air and/or dust.
Honeycomb Dial
A Rolex dial model featuring a honeycomb-like texture—See also Guilloche.
Horology
1 – The science of measuring time. 2 – The art of making timepieces.
HRD
Hoge Raad voor Diamant (HRD). HRD Antwerp (Belgium) operates six services: HRD Diamond Lab, HRD Precious Stones Lab, HRD Education, HRD Graduates Club, HRD Equipment and HRD Research. Certification company Diamond High Council.
Hue
Refers to the position of a color on the color wheel, or the dominant wavelength of color attributed to a gemstone. There are six primary hues: violet, blue, green, yellow, orange, and red. In between these primary hues are secondary hues, such as blue-green. See also tone and saturation
Hunter Case
A case used on pocket watches and even some early wrist watches, whereas the front and back are protected by hinged covers, which are usually spring loaded.