Whether you are looking to buy a piece of jewellery or a jeweller yourself, you will have probably come across the terms precious and semi-precious when it comes to gemstones and you might not be sure what these terms mean.
And it can be very confusing as you can have a $100/ct Diamond or Sapphire that are ‘precious stones’ and a $10,000/ct Black Opal or Colour-change Alexandrite that are ‘semi-precious’.
That is why I created this post to 1) hopefully clear this up and 2) hope that we stop using these stupid terms for gemstones!
What is the Difference Between a Precious and Semi-Precious Stone?
There isn’t one as there are no industry recognised definitions as to what a precious or semi-precious gemstones is as there is no clear and definitive way to say which category a gem would fall into.
But there is a commonly referred to notion of precious and semi-precious gems on many jewellers blogs, which reportedly dates back to the 1800’s, where based on their perceived value, Diamonds, Emeralds, Sapphires and Rubies were called “precious stones” and all other gemstones were called “semi-precious stones”.
The problem with this very simple ideology is that it is completely flawed and as the gem-trade and Gemmology (the study of gemstones) has continued to evolve, the notion of ‘precious’ and ‘semi-precious’ gemstones has become an antiquated one.
And the main reason for this is, which I mentioned above is that there is no clear and definitive way to decide how a gemstone would fall into either category, either from a value or gemmological perspective and even the definition of ‘semi-precious’ from two leading dictionaries doesn’t really help:
“A semiprecious stone is one that is used for making jewellery but is not extremely valuable” – Cambridge Dictionary
“of less commercial value than a precious stone” – Merriam-Webster Dictionary
Bit vague aren’t they?
So according to the Merriam-Webster definition, a statement like “Emerald is a precious stone but Alexandrite is a semi-precious stone” says that an Emerald is more valuable than Alexandrite but you simply cannot make these kind of sweeping statements.
And just looking at this from a value perspective, it would be impossible to create a definition as all of the ‘precious stones’ mentioned above can range massively in price:
- Diamond – from less than $100 per carat to over $1 million per carat
- Emerald – from less than $30 per carat to over $100,000 per carat
- Sapphire – from less than $20 per carat to over $100,000 per carat
- Ruby – from less than $40 per carat to over $1 million per carat
But there many gemstones, including:
- Colour-change Alexandrite
- Tsavorite Garnet
- Demantoid Garnet
- Black Opal
- Paraiba Tourmaline
- Imperial Topaz
Whose value can range from less than $100 per carat to thousands or even tens of thousands of dollars per carat and I don’t know about you but calling a stone with a $1,000 per carat plus price tag ‘semi-precious’ doesn’t sound quite right right to me.
There are also many gemstones such as Aquamarine, Tanzanite and Jade that can easily fetch hundreds and potentially a thousand dollars per carat but I’m not sure at what point a gem becomes “extremely valuable”?
What About Low Value Gems?
But what about the lower value gemstones such as Amethyst, Blue Topaz and Peridot, should we call these ‘semi-precious’ gems?
No, because we still don’t have a definition for what a ‘semi-precious’ gemstone is and as Walter Schuman quite rightly says in his Gemstones of the Word book (a must buy for anyone interested in gemstones), ‘semi-precious’ is quite a derogatory term.
This is because placing the term ‘semi-precious’ on any gemstone instantly devalues it in the eyes of many people and this isn’t something you want to do with any stone.
Yes, there are many gemstones out there that don’t have a lot of commercial value, mainly because that material is quite abundant but these stones can still have a lot of personal and sentimental value to the people who own them.
Valuing Gemstones
As the terms ‘precious’ and ‘semi-precious’ were formed based the perceived value of the stones, lets look at some of the factors we use to value gemstones.
When it comes to valuing a gem, there are many factors that impact the value of individual stones, such as:
- Colour
- Clarity
- Phenomenon – optical effects such as colour-change, chatoyancy or asterism
- Nature – natural or synthetic
- Treatments
And this is why two gems of the same variety can vary so much in terms of price but there are some more factors that have a much more general impact in terms of gem values.
Rarity
The first one of these is rarity and when it comes to gemstones, in most cases the rarer the stone, the more valuable it is.
And when it comes to rarity, comparing a stone to Diamond seems to be the standard as you will often see something like “xyz stone is rarer than diamond” and there are quite a few gemstones that are rarer than Diamond, such as:
- Colour-change Alexandrite
- Demantoid Garnet
- Tanzanite
- Black Opal
- Paraiba Tourmaline
- Natural Pearls
There are also some extremely rare gems such as Bixbite (Red Beryl) and Benitoite.
But I do just want to touch on Diamonds for a second here as Diamond as a gem material isn’t that rare but and it is a big but, fine gem-quality Diamonds are, especially if:
- The are large colourless Diamonds that are free from inclusions
- They posses a fancy colours such as blue, pink, red, orange or purple
Then you have the flip side of this, which is gemstones that are much more abundant, such as:
- Quartz varieties, including Amethyst, Citrine and Smokey Quartz
- Feldspar varieties, including Labradorite and Moonstone
- Almandine & Pyrope Garnets
- Peridot
To name a few and because there are lots of examples of gem-quality material available, the prices of these gemstones are usually a lot lower.
Desirability
The more desirable and in-demand a gemstone is, the higher the value but desirability is a variable that can fluctuate over time as gems go in and out of fashion and a great example of this is Sapphire.
This is because prior to the engagement of Prince William and Kate Middleton, Sapphires weren’t overly in demand but once they got engaged with the ring boasting a gorgeous Ceylon Sapphire, demand for the Sapphires increased massively and prices for high quality stones jumped accordingly.
Another factor that comes into play in terms of desirability is the origin a gemstones (where it is mined) as there are certain gems from certain locations that attract a premium over similar size and quality gems from others, some examples of this includes:
- Rubies from Burma (now Myanmar)
- Emeralds from Colombia
- Sapphires from Kashmir
This is because people believe (rightly or wrongly) that gems from certain locations are of a higher quality or rarer than the same variety of gem from another location, which makes them more desirable and thus more expensive.
Conclusion
I hope that this has post has helped in your quest for knowledge about ‘precious’ and ‘semi-precious’ gemstones by explaining why there terms don’t work and breaking down the flaws in the “commonly accepted definitions” as there is a lot of bad information online around this subject (as there is for everything!).
As I final note for this post, I once asked my knowledgeable and highly respected Gemmology tutor what the difference was between a ‘precious’ and ‘semi-precious’ stone and his response:
“There isn’t one, all gemstones are precious”
And I couldn’t say it better myself.
I'm Paul Haywood FGA DGA, a fully qualified Gemmologist and Diamond Grader from the Gemmological Association of Great Britain and a lover of all things jewellery.