Changle Sapphire

Changle Sapphire

Changle Sapphire is a geographical indication certification trademark.

　　Sapphire is an exceptionally precious resource unique to our county, boasting the largest reserves in China, with a mining area spanning 360 square kilometers. Since its discovery and extraction in 1986, successive county Party committees and governments have prioritized the jewelry industry as a key sector. Billions of yuan have been invested to establish three large-scale jewelry production, processing, and trading bases: the Gem City Grand World, Changle Jewelry Street, and the Wutu Town Gem Trading Market.

　　　Changle sapphires were formed by volcanic eruptions 18 million years ago. Their primary ore bodies mainly consist of alkaline olivine basalt. The sapphires produced in Changle are characterized by large crystal grains, intact crystals, pure color, strong dichroism, high clarity, minimal inclusions, a high number of unique gemstones, and high yield rates. The crystals are mostly hexagonal bipyramids and tabular aggregates, often forming barrel-shaped or tabular structures, with sizes typically ranging from 3 to 20 millimeters. The largest discovered crystal measures 80 millimeters in diameter and weighs over 700 carats. Due to variations in the composition and structure of basalt across different mining areas, the characteristics of the sapphires produced also show certain differences. Overall, they can be divided into two categories: ordinary sapphires and unique sapphires. Changle County has abundant sapphire reserves, with a mining area covering 450 square kilometers, making it one of the world’s rare sapphire-rich regions. The total confirmed reserves amount to billions of carats, representing the largest sapphire deposit discovered in China.

　　　　There are two types of sapphire deposits: primary deposits and alluvial sapphire deposits. Changle is unique in the world for having both primary and alluvial sapphire deposits. Primary sapphire deposits are formed when magma crystallizes into sapphire crystals under high-temperature conditions deep within the earth's crust during volcanic eruptions. These crystals are then encased within cooled lava, forming the primary sapphire deposit. Alluvial sapphire deposits are created over time through natural erosion. Exposed primary deposits are gradually weathered and eroded, and the basalt formed from magma breaks down into gravel, releasing the sapphire crystals contained within. These crystals mix with basalt gravel and are transported downhill by water flow. After being washed and carried by floods, they accumulate to form extensive alluvial deposits.