A photo of a manicured hand holding up an unheated blue Sapphire ring, encircled with two diamond halos, and a double band.

What makes a stone ‘precious’ or ‘semi-precious’?

If you’re new to the world of gemstones, the terms ‘semi-precious’ and ‘precious’ get thrown around a lot, much to the confusion of the layperson. What exactly makes one gem precious and the other, not? Why is a fine, fiery pure-red Spinel considered semi-precious while a dull, cloudy Ruby considered precious? 

We don’t blame you — this distinction didn’t exist in ancient times, and the idea of a semi-precious gem is a rather modern, 19th century lexicon. If you ask us (and other professional gemologists) these labels are rather vague, arbitrary, fluid and don’t mean much!

Citing the wisdom of Richard Wise in ‘Secrets of the Gem Trade’ (2016), a precious stone is simply one that is beautiful, rare and in high demand.


A photo of a 5 carat Emerald ring which has a Diamond on each side, held gently towards the camera.

While beauty is in the eye of the beholder, gems with the most pure, striking colours are always going to be considered the most beautiful! Imagine… gemstones are dug up from the ground so a bright, clean hue would make it special from the soil and rocks amongst them. 

In fact, if you were to consult ancient Egyptians, a stone’s colour was the only important factor for preciousness. Found buried with the Pharaohs and encased in gold are carved Lapis Lazuli intaglios and Carnelian jewels, brightly hued stones which are rather plentiful. Given that rarity and price were obviously no object for kings who were revered as gods, it’s clear that there was a different criterion in mind for preciousness. 


A Ruby cocktail ring with unfurling Diamond petals and movable rose-gold flower pistols. A fantasy flower inspired by her favourite plant, the Tillandsia.

Rarity adds a sense of exclusivity and allure, making rarer gemstones more coveted and ‘precious’ due to the lengths and costs that obtaining one entails! For example, Taaffeite, a gem you’ve probably never heard of before, is so rare that there are fewer than twenty known specimens in the world, and even fewer are gem quality specimens. Compare that to the number of people you know who own diamond rings! Diamonds aren’t as rare as you think; many coloured gems are ten times rarer, if not more!


A Padparadscha Sapphire is one of the most rare gemstones out there, yet its lesser known than its supposed 'precious stone' sibling, blue Sapphire.

In the gem world, there are different types of rarity. Some gems are hard to come by due to their sources being extinct and no longer producing, like Kashmir Sapphire or Santa Maria Aquamarine. Others are in such high demand that, even though comparatively abundant, good specimens are hard to find on the market. Say hello to the ‘Big Three’ coloured gems which are coveted all over the world!


While a precious stone is both beautiful and rare, beauty is subjective, and the phrase ‘beauty is in the eye of the beholder’ (as overused as it is) holds true especially when it comes to gemstones. The idea of what is considered precious has, after all, always been fluid and ever-changing. At MADLY, we follow our hearts. After all, the most precious gem is the one that speaks to you.