Dictionary of Geotourism

2020 Edition
| Editors: Anze Chen, Young Ng, Erkuang Zhang, Mingzhong Tian

Pearl

Reference work entry
DOI: https://doi.org/10.1007/978-981-13-2538-0_1847
In Chinese, pearl is also being called ‘real bead’. They are organic gemstones found in shelled molluscs. Pearls are made up of calcium carbonate (aragonite) secreted inside a mollusc, which forms abundant tiny aragonite crystals. Its composition is 91.6% CaCO 3, 4% H 2O, 4% organic matter and 0.4% other materials. Pearls have various forms, including round, pear-shaped, egg-shaped, teardrop-shaped, button-shaped and irregular, and round pearls are most valuable. Pearls do not have a uniform content and have various colours, such as white, pink, light yellow, light green, light blue, brown, light purple and black. White pearls are most common. Pearls have white streaks, a typical soft pearly lustre with a rainbow halo and are transparent or translucent. China was the earliest country to practice pearl aquaculture and is the largest producer of pearls, including both cultured seawater pearls and freshwater pearls. The famous ‘southern pearls’ are represented by the pearls cultured in...
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