In the 1800s gemstones were classified into two categories; precious and semi-precious. Only four were classified as precious; diamonds, rubies, sapphires and emeralds. Known as "the big four", they were considered the most expensive, rare and sought after, hence why they deserved to be called 'precious'.
Every other gemstone outside of "the big four" was considered semi-precious. The list is long, but some of the most well known semi-precious gemstones includes amethyst, aquamarine, garnet, opal, pearl, peridot, tanzanite, tourmaline & turquoise.
However many jewellery experts say this separation between precious and semi-precious has no scientific backing. For instance, emerald and aquamarine have the same chemical composition, but only emerald is considered precious. Perhaps more importantly, the distinction is said to lack real meaning, because it doesn't take into account the quality of the gemstones. Some semi-precious gemstones can be much more valuable and rare than a precious stone. For example, a low grade diamond or emerald is likely to be far less expensive than a top quality garnet. Therefore, nowadays the classification is seen as out of touch, a relic of the past, and is no longer commonly used by Gemologists.
Our Advice When Choosing A Gemstone
When selecting your perfect gemstone, our advice is not getting too caught up on whether the stone is so-called precious or semi-precious. The most important consideration is the quality of the particular gemstone - and of course that you personally love the stone you've selected. Every gemstone is completely unique, with distinct hues, tones and patterns of light, which is why we love them so much!