Most diamonds have fluorescence, usually blue fluorescence, which can be observed under long-wave ultraviolet lamp. According to GIA standard, none, weak, medium, strong and very strong can be classified as non-fluorescence. The fluorescence grade of diamonds has a great influence on the price of VS diamonds with D-G color above 50 points. Generally, weak fluorescence can affect the price by about 5%, and moderate fluorescence can affect the price by 7%-6544. Strong fluorescence has a great influence on higher colors, which can reach more than 30%. Especially strong fluorescence is basically about 35% lower than the price without fluorescence. Generally, it has a great influence on the price of diamonds with a DEF of 1-2 carats. The stronger the fluorescence, the more colorless the color is (clearer under the lens of 10 times), which affects the transparency of high-color diamonds. However, for diamonds with a color lower than J, the price will still be 5%- 10% lower. The color is as low as m, and fluorescence has little effect on the price. The price of small diamonds below 20 points has little effect, and the price of diamonds with high clarity VVS is also affected by 20-50 points. Because the National Gem Testing Center does not classify and comment on fluorescence, most of the diamonds on the market at present are not specified except those with international certificates. However, because most diamonds are imported, and the prices follow the pricing standards and market demand in the international market, many large diamonds with strong fluorescence also sell at the same price, which is a loss for consumers and unfamiliar operators.
In fact, in the newly promulgated diamond standard in China, although it is not strict, it is definitely clear. According to the light intensity of diamonds under long-wave ultraviolet, China is divided into four grades: strong, medium, weak and none. But most consumers don't understand it, so this indicator is not needed. In this way, the appraisal certificate issued by the appraisal institution generally does not indicate the fluorescent indicator. This also gives many jewelers a loophole.
However, there are also a few people abroad who like strong blue diamonds and will buy them specially. Because dark blue sometimes makes diamonds look cool.
2.GIA loose diamond, 1. 14 carats, 3EX cut, no fluorescence, my appraisal is:
If vvs1vvs2vs1vs2si1si2.
d 2 1.33 15.0 1 13.04 10.27 8.45 6.08 5. 14
e 14.62 13. 1 1 10.67 9.0 17.5 15.69 4.90
f 12.88 10.67 9.48 8. 14 6.87 5.45 4.66
g 9.88 8.85 8. 14 6.87 6.32 5.2 1 4.50
h 8. 14 7.5 1 6.87 6. 16 5.53 4.98 4.35
A 6.79 6.24 5.69 5.214.98 4.50 3.95
j 5.53 5.2 1 4.98 4.74 4.50 3.95 3.7 1
The above valuation refers to the valuation purchased in the network+physical store. If you buy it in a jewelry store, it will probably go up by about 30%.
3. Diamonds certified by GIA can basically be considered to have the same credit rating, and no jewelry brand has the high credit rating of GIA certificate. Even if it's a big brand, I won't recognize it without GIA certificate. To buy diamond ornaments above 1 carat, it is recommended not to buy them in jewelry stores, but online+physical stores to recognize GIA certificates.