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Vaginal lubrication is a naturally produced fluid that lubricates the vagina. Vaginal lubrication production increases significantly during sexual arousal in anticipation of sexual intercourse. [1] Vaginal dryness is the condition in which this lubrication is insufficient, and sometimes artificial lubricants are used to augment it. Without ...
Currently, gem production totals nearly 30 million carats (6.0 tonnes; 6.6 short tons) of cut and polished stones annually, and over 100 million carats (20 tonnes; 22 short tons) of mined diamonds are sold for industrial use each year, as are about 100 tonnes (110 short tons) of synthesized diamond.
The diamond cutting process relies heavily on this directional hardness, as without it a diamond would be nearly impossible to fashion. Cleavage also plays a helpful role, especially in large stones where the cutter wishes to remove flawed material or to produce more than one stone from the same piece of rough (e.g. Cullinan Diamond). [8]
Group of precious and semiprecious stones—both uncut and faceted—including (clockwise from top left) diamond, uncut synthetic sapphire, ruby, uncut emerald, and amethyst crystal cluster. A gemstone (also called a fine gem , jewel , precious stone , semiprecious stone , or simply gem ) is a piece of mineral crystal which, when cut or ...
The main stone, named the Graff Lesedi La Rona, is the world's largest emerald-cut diamond. It is a D-color (totally colorless), high-clarity stone weighing 302.37 carats (60.474 g; 2.1332 oz). According to Graff, the stone is the "largest highest clarity, highest color diamond ever graded by the Gemological Institute of America (GIA)". The ...
The stone is then inserted into the space, and gravers or burins are used to lift and push a tiny bit of the metal into and over the edge of the stone. Then a beading tool – a simple steel shaft with a concave dimple cut into the tip – is pushed onto the bit of metal, rounding and smoothing it, pushing it firmly onto the stone, and creating ...
Every natural diamond crystal contains impurities and typical intrinsic or "self-defects": vacancies, dislocations, and interstitial atoms. The most common impurity in diamond is nitrogen, which can comprise up to 1% of a diamond by mass. Nitrogen as a diamond impurity was first identified in 1959 by Kaiser and Bond of Bell Telephone. [1]
When designing a diamond cut, two primary factors are considered. Foremost is the refractive index (RI) of a diamond, which, at 2.417 (as measured by sodium light, 589.3 nm), is fairly high compared with that of most other gems. Diamond's RI is responsible for its brilliance—the amount of incident light reflected