Donghai Crystal

Donghai Crystal refers to the crystals produced in Donghai County, Lianyungang City, Jiangsu Province. Here is detailed information about it:

Introduction

Donghai Crystal refers to crystals or gemstones sourced from Donghai County, located in Jiangsu Province, China. Donghai is renowned for its abundant and diverse crystal deposits, making it one of the most important areas in China for crystal production. These crystals include varieties like quartz, amethyst, citrine, and other types of gemstones that are used in jewelry, carvings, and decorative items.

The region has gained a reputation for high-quality crystals, and Donghai crystal products are often exported worldwide. The crystals are not only valued for their beauty and clarity but also for their use in traditional Chinese practices, including Feng Shui and gemstone healing.

Donghai County is renowned as the “World Crystal Capital” and is a significant production area for natural crystal raw materials globally. Donghai Crystal has become a famous geographical indication product in China due to its superior quality and unique characteristics25.

Product Features

• Appearance: Generally, it has a crystalline structure with excellent carvability and polishability. It is usually transparent and glossy, presenting colors such as colorless, brown, purple, green, and yellow2.
• Hardness: With a Mohs hardness of 7, it is relatively hard and durable, making it suitable for various processing and carving techniques2.
• Density: The density is approximately 2.66 grams per cubic centimeter2.
• Refractive Index: Ranging from 1.544 to 1.5553, it exhibits good optical properties, resulting in bright and sparkling visual effects2.
• Purity: The silicon dioxide content is higher than 99.99%, with impurity content less than 20 ppm and aluminum content less than 15 ppm, indicating its high purity2.

Geological Origin

Approximately 600 million years ago, during the Early Proterozoic Era, the area of Donghai County was underwater. Sediments from Shandong were deposited, forming the basement rock system of the Donghai Group. In the late Proterozoic Era, due to the Wutai crustal movement, accompanied by the intrusion of ultrabasic and basic magma, new and old minerals collided, recombined, and became enriched, giving rise to non-metallic minerals like crystal. Subsequently, during the Jurassic and Cretaceous periods, the Yanshanian crustal movement led to the formation of the Tanlu Fault Zone, providing favorable tectonic and material conditions for crystal formation. Eventually, about 100 million years ago, volcanic activities brought these crystals closer to the Earth’s surface2.

Production and Processing

• Mining: Donghai County has abundant crystal resources, with an estimated reserve of over 300,000 tons. The mining process involves careful extraction to preserve the integrity of the crystals25.
• Processing: There are more than 3,000 crystal processing enterprises in Donghai County, employing nearly 300,000 people. These enterprises utilize advanced techniques such as laser engraving, sandblasting, as well as traditional carving methods like three-dimensional round carving, relief carving, and hollow carving, to create a wide variety of crystal products, including jewelry, handicrafts, and ornamental pieces24.

Cultural Significance

• Historical References: Donghai Crystal has a long history and is often mentioned in ancient Chinese literature, such as in the works of Su Dongpo and Wu Chengen, demonstrating its profound cultural connotations2.
• Artistic Value: The unique properties of Donghai Crystal, such as its clarity, color, and inclusions, provide rich materials for artistic creation. Crystal carvings from Donghai not only showcase exquisite craftsmanship but also embody traditional Chinese cultural values and aesthetic concepts2.
• Festival Tradition: Since 1991, Donghai County has held the Donghai Crystal Festival every two years, which has become an important platform for promoting crystal culture, displaying crystal products, and strengthening exchanges and cooperation in the industry