What significant milestone, represented by a precious gem, did Queen Elizabeth II commemorate in 2012?

Okay, let's talk about royal jubilees! In the UK, we mark significant milestones in a monarch's reign with special celebrations. These anniversaries are traditionally associated with precious materials, each representing the length and importance of the reign. Think of it like this: the longer the reign, the more valuable the material. Queen Elizabeth II, having reigned for an impressive 70 years, had several jubilees. The Silver Jubilee marks 25 years, the Golden Jubilee is for 50 years, and the Diamond Jubilee celebrates 60 years on the throne. This Diamond Jubilee was a huge event in 2012, with celebrations across the UK and the Commonwealth. Now, while a Platinum Jubilee does exist, it marks 70 years, and that wasn't until 2022. A Pearl Jubilee, marking 30 years, is also a real jubilee, but it wasn't the one celebrated in 2012. So, because the question specifically asked about the milestone in 2012, which was her 60th year as Queen, the Diamond Jubilee is the correct answer.