首页>英语角 > 听力 > 美音 > 课 程 > 社会 > 大四>How to examine a diamond
How to examine a diamond
Question
What is used to grade a diamond?
提交
00:00
00:00
View the diamond unmounted so you can examine it from all angles. If it's mounted in a setting, have it removed.
Jewelers use diamond tweezers to examine diamonds because they have fine, grooved tips for traction and have a locking mechanism so the diamonds won't pop out when handling. To pick up a diamond with tweezers, place the diamond face down on a clean, flat surface and position the tweezers on either side of the diamond's widest part, or "crown." Gently push forward the tweezers slide lock until it barely catches. You don't want to press too hard. You could damage the diamond's edge, or even send it flying.
Inspect the diamond first by eye to try spot any major defects. If you do this after viewing with magnification, your eyes will only see what they expect to see.Also, move the diamond away from the jeweler's army of bright lights which will pretty much make frozen spit sparkle. Walk the diamond over to a window to see how it sparkles there by comparison.
Diamonds are graded with a jeweler's loupe (pronounced loop). This basically a hand held magnifier that is fully corrected so that there is no distortion. Loupes, though, are very hard to master and it's much easier for you to use a binocular microscope instead. If you do use a loupe, make sure that it is 10 power as some jewelers might give you a 5 or 2 power one so you can't see a diamond's flaws as well.The first thing to know about using a jeweler's loupe is that you can look through it from either side; they are both the same. Bring the loupe right up to your eye in one hand and hold the diamond in the other, positioning the diamond about one inch away from the loupe until the entire interior of the diamond is in clear view.Keep your head up as if you were talking to someone so you will not block out the light from hitting the diamond.Ideally, you want the strongest light source to pass through the side of the diamond. When viewing the color of the diamond use only daylight balanced light as incandescent lights will give off a yellow color.
When determining the body color of the diamond, place the diamond face down on a white background. Look through the slanting sides going up to its point, the "cone" of the diamond. Notice how saturated the color is at the thickest points. This is the only way to judge a diamond's true color, as many diamonds will appear white when looked at face up.After you have inspected the diamond and it all looks good, make sure that it comes along with a grading certificate. This is a written document from a creditable gemological lab, like the Gemological Institute of America (GIA), that delineates the diamonds clarity, color, cut, and carat weight, among other things. With this certificate in hand, you know exactly what you are buying.
视频文本已隐藏,本文本来自网络或网友仅供参考
显示视频文本

Discuss

0 comments
characters remainingSubmit
反馈