I have a complicated relationship with jewellery trends. On one hand, I find them genuinely interesting. On the other hand, I have a drawer full of evidence that chasing trends in jewellery is an expensive hobby that leaves you with a lot of pieces you wore twice and now feel nothing about. The difference between jewellery worth buying and jewellery worth investing in is a distinction I started paying proper attention to a few years ago, around the same time I started thinking more seriously about where my money goes in general. I invest in stocks and mutual funds with a long-term horizon. I buy books I will reread. I…