The specific gravity is 12, which is lighter than platinum and has strong ductility. Melting point 1555℃, hardness 4-4.5, slightly harder than platinum.
Chemical properties are relatively stable, insoluble in organic acids, cold sulfuric acid or hydrochloric acid, soluble in nitric acid and aqua regia, and it is not easy to oxidize and lose luster under normal circumstances.
Platinum, element symbol Pt, silver gray, specific gravity 2 1.35,
Melting point 170℃, Mohs hardness 4-4.5 degrees, stable chemical properties, not corroded by acid and alkali except aqua regia.
Pure platinum is relatively soft, and the addition of metals such as ruthenium, rhodium and palladium will increase its hardness.
Their prices differ by more than half, platinum 360 yuan/gram, palladium 180 yuan/gram. The difference is that platinum is more valuable than palladium, and the prospect of palladium is not good Moreover, gold shops in most places do not recycle, so it is not as shiny as platinum after wearing it for a long time.
As for diamonds? According to the different quality, the newly promulgated national standard GB/T 16554- 1996 stipulates that there are four factors to evaluate the diamond grade, namely, the color, purity, cut and carat weight of the diamond. These four factors are also called "4C" criteria. "4C" is the first letter C in four English terms: color, clarity, cut and carat weight. 4C is an indispensable comprehensive factor to evaluate the quality of a diamond, and it is also a measure for consumers to judge the value of a diamond. There are all kinds of diamonds in the jewelry market, including pure natural diamonds and irradiated and filled diamonds. There are white diamonds (actually colorless with white characters on a white background), yellow diamonds, and red, green, blue and orange colored diamond. From the shape, there are standard round diamonds, as well as heart-shaped, oval and pear-shaped diamonds. The most common diamonds in the market are white (colorless) standard round diamonds, so in the "4C" standard, the classification of diamond color, clarity and carat weight only refers to the classification of natural white (colorless) to light yellow (brown, gray) series polished diamonds with carat weight greater than 0.2, while the cutting classification only refers to standard round diamonds or white (colorless) to light yellow (. The "4C" standard is not applicable to the classification of colored diamonds, irradiated diamonds and filled diamonds. In the "4C" standard, the color of diamonds is divided into 12 grades. The grading method is: the pure colorless diamond is defined as the highest color pole-extremely white, 100 color, which can be expressed by D or written as D( 100). With the increase of the yellow component of diamonds, the color grades gradually decreased to E(99), F(98), G(97) and H(96). In the diamond appraisal certificate, the color grade is usually expressed only by English letters. When the color grade is lower than n, it is generally considered that the diamond is no longer suitable for cooperative jewelry. The color grading of diamonds is determined by professional technicians who compare the diamonds to be graded with standard colorimetric stones repeatedly in the grading environment of specified standards. Or use a colorimeter to scan the diamonds to be classified in the visible range, and then determine them through a series of technical analysis and processing; The purity of a diamond is its purity. The higher the purity of a diamond, the less impurities, defects or flaws there are, and vice versa. Objectively speaking, flawless diamonds are rare. According to the standard, carefully observe the internal and surface defects of the diamond to be graded with a magnifying glass of 10 times. Under this condition, the clarity of diamonds can be divided into five grades: flawless LC, extremely defective VVS, slightly defective VS, defective SI and severely defective P, and further subdivided into sub-grades 10, namely LC, VVS 1, VVS2, SI 1, SI2 and P. Diamond cutting refers to the proportion and decoration degree of cut diamonds, which is an index directly influenced by human factors in 4C standard. The brilliance of diamond is attributed to its unique high refractive index and high dispersion (commonly known as "fire color"). Only excellent and proportional cutting can make all the incident light reflect, so as to show the unique luster, luster and flash of diamonds to the maximum extent. If the cutting is rough and disproportionate, it will cause "light leakage". Even if a diamond has good color and clarity, it can't have good light and its value. The simple way for consumers to judge the cutting quality is to pick up the diamond and stare at the shining light on the top of the diamond. If there are not many colors, the cutting is not ideal. According to the standard, cutting is divided into three grades: very good, good and average; The unit of mass (commonly known as weight) of diamonds is grams, but "carat" is still used as the unit of mass (weight) of diamonds in international diamond trade. 1 carat = 200mg = 0.2g. 1 carat is divided into 100 parts, and each part is called10.8. When the color pole, clarity and cutting conditions are similar, with the increase of diamond weight, its value increases geometrically. Consumers should choose diamonds of suitable size according to their hobbies and actual conditions.
Cutting has a great influence on the price of diamonds. Usually, the price difference of diamonds with the same quality, color, clarity and cut is within 3%. The price difference of diamonds with the same quality and different color grades is 20%-30%; The price difference of different cuts is 30%-40%. For example, a diamond with 1 carat color, clarity and cut is 70%-80% different from a diamond with 1 carat color, clarity and cut. "From this perspective, the quality of diamond cutting can affect the price of diamonds by about 40%, which is the most influential factor in the" 4C "standard for evaluating diamond grades. According to experts, diamond cutting is the ultimate standard to reflect the quality of diamonds, and it is the only human factor that affects the price of diamonds. Diamond cutting can show its dazzling fire color better than clarity and color grade. Excellent cutting makes diamonds shine, while inferior cutting diamonds are dull, because diamonds are octahedral and dodecahedral blanks before cutting and forming. Through accurate calculation, careful design and excellent cutting in perfect cutting, the gross weight of diamonds is greatly lost. In order to keep the weight as much as possible, some merchants do not cut according to the diamond standard, so the price of diamonds with the same color, quality and weight may be about 40% different due to different cutting. Most consumers will use the carat weight of diamonds to compare the prices of diamond ornaments in different stores, while ignoring other factors that determine the price of diamonds (such as 4C). In fact, when you buy a diamond ornament, you pay not only the price of the diamond itself, but more importantly, it includes the design of the diamond ornament and the exquisite craftsmanship of the craftsman. Moreover, the services and operating costs provided by each jeweler are different, and the prices are also different. So you should choose a trusted professional jewelry store to help you find the right diamond, which is more important than the price.