The Jewellery Quarter is an area of central Birmingham, England, in the north-western area of Birmingham City Centre, with a population of 19,000 in a 1.07-square-kilometre area. The Jewellery Quarter is Europe's largest concentration of businesses involved in the jewellery trade and produces 40% of all the jewellery made in the UK. It is also home to the world's largest Assay Office, which hallmarks around 12 million items a year.