Ruyu Jewelry Store Dongruyu Jewelry Store was formally established on August 24, 20 12. Long development time and rich experience. Zhangmutou topaz is of high quality and can meet the different needs of the masses. Dongguan is a prefecture-level city under the jurisdiction of Guangdong Province and a megacity. Dongguan is located in the south of China, south-central Guangdong Province, on the east bank of the Pearl River Estuary, bordering Guangzhou in the northwest and Shenzhen in the south.