Infinite rough diamond: a single diamond that has been cut, polished but not set.

Clarity (clarity)

Clarity refers to the cleanliness of the inside and surface of a diamond. There are two factors that affect the clarity of diamonds:

Internal defects: crystal inclusions, clouds (a collection of many tiny crystals), feathers (internal cracks), bands, etc.

External defects: original crystal plane, redundant crystal plane, scratches, polishing marks, damages, notches, worn crystal plane edges, growth lines, multi-slice twins, etc.

When evaluating cleanliness, attention should be paid to the number, color, size and location of defects.

(1) diamond clarity grading conditions:

① Diamonds should be scrubbed with alcohol, propane and nylon soft cloth;

(2) under the magnifying glass of 10 times, which can be observed under the microscope above VVS level;

(3) Using colorimetric lamps or fluorescent lamps, light enters from the exhibition hall;

(4) Personnel should be specially trained.

(2) Clarity grade of diamonds:

Diamond clarity grading standards of International Jewelry Federation, American Gemological Institute and China. In these standards, diamond clarity is generally divided into five grades:

① Flawless LC under microscope LC: 10/0 times under magnifying glass, there are no flaws inside and outside;

② Very slight defect level VVS: under the magnifying glass of 10 times, there are very slight defects;

③ Defect grade VS: 10 times under the magnifying glass, there are tiny defects;

④ Micro-defect Si: 10 times magnifying glass with obvious defects;

⑤ Grade P (also called Grade I): Defects visible to the naked eye.

The grade of diamonds mainly depends on 4C, namely:

Color: Diamonds have many natural colors, from precious colorless (white after cutting) to rare light blue, pink to yellowish. The brighter it is, the more white light can be transmitted, and the richer the color is after refraction and dispersion. The grading of diamond color is determined by technicians repeatedly comparing the diamond to be graded with the standard color colorimetric stone in the grading environment of professional laboratories. The whitest diamond is classified as D (starting from the initial of the diamond), and * * is divided into 1 1 grades, which are D, E, F, G, H, I, J, K, L, M and N in turn.

Cleanliness: Diamonds are crystallized from mantle magma deep in the earth, with complex environment, diverse components and extremely high temperature and pressure. After hundreds of millions of years of geological changes, the color, quantity, size and location distribution of various impurities will inevitably have different degrees of influence on the clarity of diamonds. Usually, a magnifying glass with a magnification of 10 is used to subdivide the clarity level of diamonds, and it is not inlaid as LC, VVS 1, VVS2, VS 1, VS2, SI 1, SI2, P 1, P2 and P3 * * * 655. Diamonds are divided into five grades: excellent, good, medium and good.

Turner: The brilliance of diamond is attributed to its unique high refractive index and high dispersion. However, uncut diamonds are just plain in appearance. Only through accurate calculation, careful design and perfect cutting and polishing can light be fully reflected from the top surface and beautiful diamonds shine. Diamond is a hard substance, indestructible and never worn. Once cut and ground, it will shine forever. The level of lathe work is divided into: very good, very good and average.

Carat weight: The weight of a diamond is measured in carats (also called carats). 1 carat = 200mg = 0.2g. 1 carat is divided into one hundred parts, and each part is called one point. 0.75 carat is 75 cents, and 0.02 carat is 2 cents. Other things being similar, with the increase of diamond weight, its value increases geometrically; Diamonds with the same weight have different values due to different colors, cleanness and cutting.