History · Geology
About Lianyungang Sapphire Field
The Lianyungang Sapphire Field in Jiangsu Province is one of China’s notable sapphire (corundum) localities. Active as a small-scale collector source since the 1980s, the field produces blue, green, and yellow sapphire from alkali basalt-hosted xenocrysts. Lianyungang complements the Donghai Crystal District as a second major Jiangsu locality entry.
Geology & Signature Specimens
Sapphire xenocrysts are hosted in Cenozoic alkali basalt flows of the Subei (Northern Jiangsu) volcanic province. Crystals are typically rounded barrel-shaped or hexagonal prisms eroded from the host basalt and concentrated in adjacent placer deposits. Color varies from blue (Fe-Ti) through green (Fe) to yellow (Fe + Cr). The Subei volcanic field is geologically related to the Cenozoic North China rift system.
