钻石的参数和鉴别(国外英文资料).docVIP

钻石的参数和鉴别(国外英文资料) Carat, or card, Cara, from 1907 internationally agreed to gem measurement unit began to continue to use. It is the quality unit of precious stones such as pearls, jade and diamonds, and the proportion of [1] of precious metals. 1. (weight unit of diamond etc.) carat (=200 mg) 2. (purity of gold unit) open, percentage purity is 24, if 18 open, purity is 18/24=75% The international standard measure of weight of diamonds is the carat, English carat, usually abbreviated to ct. 1 carats =200 mg =0.2 grams. 1 minutes, =2 mg A diamond weighing less than 1 carats is usually used as a unit of measurement (point), 1 carats =100 points. On the diamonds certificate, the weight of the diamond is exactly third after the decimal point. What is a diamond?: Diamond is a crystalline mineral, similar to graphite, consisting of carbon (chemical element C) in nature. Of all natural minerals, diamonds have the highest hardness, and although the diamond is hard, it is brittle because of its brittleness. A diamond crystal can easily be crushed by a hammer. Of all substances, diamonds have the highest thermal conductivity. Even metals such as silver and copper have less heat conductivity than diamonds. In addition, diamond is difficult or will not expand when heated. Diamonds burn when temperatures range from 700 to 800. In an oxygen free environment, when the diamond is heated to about 1500, the diamond turns into carbon. Two, diamond grade: The diamond is rated at 4C. 1, weight (carat, Caratage, identification identified as CT), needless to say, of course, the heavier the better. 1CT equals 100 points. 2, color (Color), there are international standards, from the beginning of D, basically to Z so far, Z below the general as industrial drilling, that is often referred to as diamond. 3, cleanliness (Clarity), commonly used in the international IF, VVS, VS, SI, I, respectively, as explained: A and IF are perfect and flawless, and are not visible at ten times the magnifying g