A natural pearl
A natural pearl or wild pearl is one china chengdu weather that forms without any human intervention at all, in the wild, and is very rare. Many hundreds of pearl oysters or pearl mussels have to be gathered and opened, and thus killed, in order to find even one wild pearl,cheap wedding dresses and for many centuries that was the only way pearls travel chengdu were obtained. This was the main reason why pearls fetched such extraordinary prices in the past.jewelry factory A cultured pearl is formed in a pearl farm, using human intervention as well as natural processes.
A variety of pearl shapes, round, pear, egg, teardrop-shaped, button-shaped and arbitrary-shaped, in which round is better. Non-homogeneous body. Colors are white, pink, yellow, light green, light blue, brown, lavender,weather in chengdu china black, etc., in white. White streaks. With classic pearl luster, soft gloss and color with a rainbow halo. Transparent to translucent. Refractive index 1.530-1.686, birefringence 0.156. No chromatic aberration. Hardness 2.5-4.5. The density of natural freshwater pearls generally 2.66-2.78g/cm3, differ by origin. No cleavage. Toughness than really making pearl jewelry (18) well. Significantly in the short-wave UV light pearl white, yellow, light green, blue fluorescent, black light pearl hair red fluorescence;south sea pearl X-ray fluorescence under white light yellow. Case of hydrochloric acid bubbles.
One family of nacreous pearl bivalves – the pearl oyster – lives in the sea, while the other – a very different group of bivalves – lives in freshwater; these are the river mussels such as the freshwater pearl mussel. Saltwater pearls can grow in several species of marine pearl oysters in the family Pteriidae. Freshwater pearls grow within certain (but by no means all) species of freshwater mussels in the order Unionida, the families Unionidae and Margaritiferidae.
Natural pearls cylindrical spherical, oval, irregular, spherical or oblong, 1 to 6 mm in diameter. Surface white, yellow white, light pink,cheap women shoes light blue, etc., with beautiful color glossy and smooth. Ornaments made of pearls, the central most have perforation. Quality hard, hard breaking, section layered. With the fire of a popping sound. Gas-free, taste slightly salty. Cultured pearls and natural pearls shape similar to, but the surface gloss is weak, the central section of a circular sand or crushed abalone,wholesale cheap fashion jewellery the surface layer of a pearl book. Medicine only pearl layer. Gas-free, taste slightly salty. But now the emergence of Hepu eco pearl greatly improved the quality of pearls!
The unique luster of pearls depends upon the reflection, refraction, and diffraction of light from the translucent layers. The thinner and more numerous the layers in the pearl, the finer the luster. The iridescence that pearls display is caused by the overlapping of successive layers, which breaks up light falling on the surface. In addition, pearls (especially cultured freshwater pearls) can be dyed yellow, green, blue, brown, pink, purple, or black. The very best pearls have a metallic mirror like lustre