How to evaluate the quality of diamond quality diamond evaluation criteria
The greater the weight of the diamond, not only the higher the price, but also the more precious itself. Generally taken to more than 100 karats of diamonds, it is necessary to report, published in the world, and some have become the world famous drill. Such as “Curry South”, “Nobility” and “Chang Lin Diamond” and so on.
Diamond “4C ” mainly refers to the evaluation of four factors Amulette de Cartier Ring Replica of diamond, they are color (color), blemishes (also known as cleanliness, clarity), cut (also known as Cut, Cut) and weight (Carart) Because the first letter of each word in English is “C”, so in the jewelry industry, commonly known as “4C”.
How to evaluate the quality of diamonds
(1) Color: color is very important to measure the quality of diamonds. As precious stones, diamonds are generally colorless (very white or whitening), or close to colorless (white), yellowish white, light yellowish white, light yellow and yellow five. In addition, with red, pink, blue and green diamonds, collectively known as Yan drilling, most of the rare treasures and was collected. In general, with black diamonds, can only be used in the industry when the abrasive.
The world’s diamond color division, there are two main systems. One set is the color grading system used in our country, this system will be very white as 100, 99 color; excellent white as 98,97 color, white as 96 color; yellowish (brown, gray) white as 95, Color yellow (brown, gray) white as 93,92 color; light yellow (brown, gray)
Color is set to 91, 90 color; yellow (brown, gray) color set to <90 color, generally <90 color level diamond is not precious stones. Another system is developed by the American Gemological Institute (GIA), the world’s vast majority of countries using the color grading system. It will be colorless diamonds as D, followed by close to colorless, and gradually to the light yellow evolution, the word
The parent is also starting from D for E, F, G, H … to Z. China’s 100 is equivalent to its D color; 99 is equivalent to its E color; 90 is equivalent to its N color.
(2) flaws (cleanliness): refers to the degree of diamonds inside and outside the inclusions, inclusions determine the level of diamond flaws. It is mainly based on diamonds in 10 times the magnifying glass to observe the results of the division, China’s diamond clarity is divided into microscopic flawless grade LC, very slightly flawed VVS, slightly flawed VS, defective SI and defective grade P And so on five grades. When viewing diamond flaws, pay attention to the size of the inclusions, the number of locations and colors. In general, the smaller the inclusions, the fewer the number, the less obvious the position, the lighter the color the better.
(3) Weight: The weight of the diamond is carat, I carat equal to 0.2 grams. The weight is usually measured with a precise diamond scale. The price of diamonds is of great importance to the size of the weight; the value of the diamonds is proportional to the square of the weight. For example, in 1978 in the northeastern part of Lesotho, Lethorat mine, found a weight 130.08 karats of colorless diamonds, valued at $ 1.15 million. While the same year in South Africa’s Prile Mill mine, found a weight of 353.9 carats of diamonds, and clean and flawed, named “the first rose” its value of 12 million US dollars. “The first rose” weighs 2.72 times the previous one, but the actual price is 10.4 times it is due to the “first rose” quality is particularly good reason.
(4) cut (cut type): refers to the proportion of diamond cutting. Good www.ourlovestore.com cut is according to the standard ratio of cutting, the main processing into a standard round diamond type (or ideal type). This kind of cut diamonds, its “fire” is the best. If not according to the standard proportion of cutting. Cut out of the diamond “fire” bad, diamonds can not shine, seem not bright, “dull”, of course, its value is low. Standard round diamond cut, a total of 57 or 58 faces. 0.25 carat below the small drill, the bottom often no small surface, so only 57 faces, and 0.5 carats above the diamonds. The bottom has a small surface, so there are 58 face.
In short, the diamond “4C” is the main basis for evaluating the quality of diamonds, in the evaluation of the need to be considered, not just one and not the other.
Diamonds are different in size, different shapes, radiant, which is the common characteristics of diamonds, but also imitation drill with the characteristics of a lot of people in the collection of diamonds, happy mood has not received the news of the diamond fake People marvel, in the investment of something precious things at the same time, but also bear the risk of investment.
What are the main types of diamonds?
According to the production of diamonds, diamonds can be divided into:
What are the main varieties of diamonds
(1) the original diamond: produced in kimberlite and potassium magnesium porphyry in the original diamond.
(2) secondary drilling: produced in a variety of sand in the diamond.
(3) synthetic drill: synthetic diamond.
(4) artificial drilling: artificial with other raw materials imitation of diamonds.
What kind of diamond is good?
Differentiated diamonds are mainly based on the color, flaws and properties of diamonds.
According to the color of diamonds, diamonds can be divided into pure rhinestones and Yan drilling. The so-called net diamond, refers to colorless transparent diamonds. Yan drilling is distinguished according to its color, such as red, is called red diamond; green, blue, golden yellow, are known as green diamond, blue diamond and diamond.
According to the number of diamonds contained in diamonds, diamonds can be divided into the following levels (also known as clarity level):
(1) mirror flawless grade LC
Under the magnifying glass 10 times, the inside and outside of the diamond are flawless.
(2) very slightly flawed VVS
Under the magnifying glass 10 times, the diamond has a very small flaws, according to 10 times the magnifying glass to observe the very small degree of difficulty, but also broken down into VVS1 and VVS2 level.
(3) slightly flawed VS
Under the magnifying glass 10 times, the diamond has a small flaw, and then observe the degree of difficulty of small flaws, but also broken down into VS1 and VS2 level.
(4) Defective SI
Under the magnifying glass 10 times, the diamond has obvious flaws, and then observe the degree of difficulty of these flaws, can be divided into SI1 and SI2 level.
(5) heavy defect level P
From the diamond crown observation, the naked eye can be seen as defective P level, and then according to the degree of obvious defects (divided into obvious, very obvious and very obvious) is divided into P1, P2 and P3 level.
Gemstone raw materials, can be used to process pondering into precious stones, entirely depends on the gemstone raw materials in all aspects of the conditions can not meet the requirements of modern technology processing. To sum up, technical processing requirements are the following aspects:
(1) color: as a gem one of the necessary conditions, the color to be uniform and pure, bright and bright light better, otherwise the quality will be reduced, or even as a gem. For colorless gemstones, the same requirements are uniform, pure, without variegated, with or without blemishes.
(2) Transparency: Transparent or translucent, generally with high transparency. But for a special optical effect (such as cat’s eye effect, star effect, etc.) gem, even if opaque can.
(3) Hardness: as a gem to the hardness of the better. At present has been found in the finest of its Mohs hardness are more than 6, such as diamonds, rubies, sapphires, gold emerald and other precious stones Moore hardness are more than 8. In short, the general requirements of the stone material Moore hardness should be more than 4, a few with a special optical effect can be slightly reduced. Mohs hardness is very small, generally for the collection (or appreciate the gem), and difficult to make daily wear jewelry.
(4) weight and particle size: for the processing of pondering the need, generally require particle size greater than 5 mm, precious in more than 2 mm. For the weight of the gem, the general requirements of the weight greater than 7 karats, especially precious stones (such as diamonds, rubies, etc.) also require about 0.25 kt.
(5) special optical effects: for color, color, discoloration, star color and other special optical effects of mineral crystals, as long as the particle size is satisfied with the technical processing, can be used to make gems.
Gem processing process
First, the choice of materials: According to experience will be gem city raw materials sorting.
Second, the raw material processing: the selected raw materials through high temperature processing, the gem of raw materials, the color lighter or deepening.
Third, cutting: the irregular stone cut into the required shape and thick, thin.
Four, billet: the cut gem raw materials rough grinding into the required shape, sub-blue and green surface.
5, plastic surgery: the blue and green surface will play the rough blank trimmed into a regular shape and size.
Six, angle: the whole shape, size of the gem for fine processing, grinding a good scale, polished.