Ziyang Blue-Black Slate

Ziyang Blue-Black Slate

Ziyang Blue-Black Slate is a protected geographical indication product.

　　Ziyang Blue-Black Slate, a specialty of Ziyang County, Shaanxi Province. Slate is an emerging eco-friendly decorative stone material of the 21st century. Due to the unique geological structure of the Qinba Mountain region, the county boasts abundant slate resources, with large reserves and a wide variety of types, among which Ziyang Blue-Black Slate is of the highest quality. Ziyang is the central zone of tile slate ore deposits in Asia and the processing and trade hub of tile slates. The county’s theoretical reserves of slate amount to 6 billion cubic meters, featuring a full range of varieties, diverse patterns, large scale, easy extraction, and low cost. There are over 20 slate production enterprises in the county, with an annual output of more than 1 million square meters of slate, and the products are exported to developed countries such as the United States and the United Kingdom. Ziyang slate is hard in texture, naturally colored, pressure-resistant and wear-resistant, corrosion-resistant, and free of radioactive substances. It is a top-grade building and decorative material. Building villas with Ziyang slate has become a pursuit and symbol of civilization for many wealthy individuals in Europe and America.

　　The people of Ziyang have been using slate to create their lives for thousands of years. According to evidence, as early as the pre-Qin period, the people of Ziyang used wooden pillars and beams, stone slabs to shield against wind and cover houses, and stones to make tables, chairs, stools, and other household items. By the 21st century, there are still many well-preserved ancient slate dwellings in Ziyang’s folk culture area. The Shaanxi Artists Association has designated this place as a sketching base, attracting nearly a thousand painting and photography enthusiasts for creation and sightseeing every year.

　　Slate resources in Ziyang are distributed across more than 20 towns in the county, with prospective reserves of no less than 6 billion cubic meters. As of the early 21st century, it is the county with the largest reserves and most concentrated distribution of blue-black slate in the world. Its main indicators, such as water absorption rate and dry compressive strength, far exceed international standards. It is one of the main export-earning varieties of Ankang City and has been exported to 11 countries including the UK, the US, France, Germany, Australia, and Spain. By the end of the 20th century, it had secured the right to export foreign trade, and the products of four manufacturers were designated as export-exempt products by the state. The brand registered for its products in the US is “Black Diamond,” and in the UK, it is “Queen.” The average selling price in the European and American markets is $30 per square meter, and it has become one of China’s top 13 stone bases. Since the 1990s, the county has promoted the rapid development of the slate industry through attracting investment, introducing advanced production technologies, and expanding production scale. A total of 12 slate production enterprises above designated size, including Beijing Xianghe Building Materials Co., Ltd., Shaanxi Dongmu Slate Co., Ltd., Shaanxi Nature Slate Co., Ltd., Ziyang Huanyu, and Sunshine Slate, have invested and developed within the county. The county now has 35 slate production enterprises. According to statistics, in 2005, the county’s slate output reached 1.6 million square meters, with an output value of 80 million yuan and foreign exchange earnings of 11.2 million US dollars for the country.

　　Product Honors

　　From the overall situation of the world's major slate-producing countries today, whether in Germany or Spain, Ziyang Blue-Black Slate has strong competitiveness in both quality and output. Many world-renowned buildings such as the German Parliament Building and the British British Museum are built with Ziyang Blue-Black Slate. In the UK, many landmark buildings and model constructions use Ziyang’s natural blue-black slate for roof covering and wall decoration. As early as 2000, Ziyang’s natural blue-black slate attracted widespread attention from the commercial circles of Spain, the world’s largest slate producing and exporting country, which sent inspection teams twice. In 2003, Spain’s Yaber Company officially established a mine in Ziyang and founded Shaanxi Ziyang Yaber Slate Development Co., Ltd. Moreover, among the more than 10 slate development enterprises above designated size in Ziyang, most are Sino-foreign joint ventures, and 95% of their products are exported for sale abroad.

　　Stone Characteristics

　　Slate: A metamorphic rock formed from claystone, sedimentary shale (sometimes quartzite), with fine mineral grains, thin and brittle, typically black, gray, or green. Slate is the commercial name for rocks that can be split into slabs, commonly known as tile slate, flagstone, or bluestone. In petrology, it belongs to the argillaceous metamorphic rock category. Slate is formed by the regional low-grade metamorphism of claystone, siltstone, or intermediate-acidic tuff. Slate comes in a variety of colors, including light blue-green, black, light green, pink, brownish-red, light gray, and yellow. Slate has a unique platy structure—slaty cleavage. Along the cleavage, it not only splits easily but also results in a very smooth surface. Slate not only has rich cleavage but is also hard in texture, elegantly colored, low in water absorption, and free from radiation pollution. It features a matte finish, slip resistance, acid and alkali resistance, fire and cold resistance, weathering resistance, and good workability for joining.

　　The structure of slate is flaky or massive, with fine grains, typically in a cryptocrystalline structure with particle sizes between 0.9-0.001mm. It is relatively dense, and most grains are directionally arranged. The rock cleavage is highly developed, with uniform thickness, moderate hardness, and low water absorption. Its lifespan is generally around 100 years. Slate colors are mostly solid hues.

　　Protected Geographical Indication Product

　　　In accordance with the "Regulations on the Protection of Geographical Indication Products," the General Administration of Quality Supervision, Inspection and Quarantine organized the review of the application for the protection of Ziyang Blue-Black Slate as a geographical indication product. Upon passing the review, it was approved to implement protection for Ziyang Blue-Black Slate as a geographical indication product starting June 29, 2007 (Announcement No. 101 of 2007).

　　 Protection Scope

　　　　The protection scope of Ziyang Blue-Black Slate as a geographical indication product is based on the range proposed in the "Letter on the Proposed Scope of Protection for Ziyang Natural Blue-Black Slate as a Geographical Indication Product" (Zi Zheng Han [2006] No. 11) issued by Ziyang County, Shaanxi Province. It covers the administrative regions of eight towns in Ziyang County, Shaanxi Province: Chengguan Town, Hongchun Town, Xiangyang Town, HuanGu Town, Haoping Town, Dongmu Township, Liaoyuan Township, and Miaohe Township.