The fact that diamond prices have risen 67% since 1978 might lead some to assume they’re a good investment. However, this 3,000-foot view of the market masks its true nature. Not only are prices extremely volatile – shooting up 249% from 1978 to 1980 before falling 77% by early 1986 – but the value of diamonds has also long been propped up by a number of artificial sources.
When you further consider that the S&P 500 has increased 2,080% since 1978, it becomes clear that diamonds are not investable under most traditional definitions, which typically necessitate safety of principal and a competitive return. That’s not to say diamonds aren’t valuable or important – especially as emergency currency and a means of abiding by societal conventions. They simply should not be purchased as an investment with the idea of retained value.