9ct Gold — The UK's Everyday Jewellery Standard
9 carat gold (375) is only 37.5% pure gold, alloyed heavily with copper, silver and other metals — the legal minimum that can still be called "gold" in the UK. That lower gold content makes it the most affordable and scratch-resistant option, which is exactly why it dominates UK high-street jewellery: signet rings, chains, earrings and everyday pieces from most British retailers are 9ct unless stated otherwise.