What determines the price of rubies? | BNT Diamonds
What are the factors determining the price of rubies

What determines the price of rubies?

16 Jul 21
  • What are rubies?
  • What determines the price of rubies?
  • Why invest in rubies?
  • Choosing between rubies, red diamonds and pink sapphires

Gemstones such as diamonds, sapphires, rubies and emeralds are known for their scarcity and their high score on the Mohs Hardness Scale. They are not only to be set in jewellery but also to represent a resilient investment in times of crisis, with profitable long-term prospects. The price of rubies per carat is the most expensive in the coloured gemstones category, and this makes them a desirable investment. What exactly determines the price of rubies, and how does the price relate to the value of rubies?

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What are rubies?

Just like sapphires, rubies are a variety of the mineral corundum - a colourless mineral in its purest form which is transformed by the presence of chrome causing the deep red colour of rubies. The red colour varies from deep red, to pink, and reddish brown. Rubies are mined on various continents, but the Mogok Valley in Myanmar is the best-known location for mining rubies and is the source of the world's most legendary ones. For example, the centre stone in Cartier's "Sunrise Ruby and Diamond Ring" is a 25.59 carat deep-red ruby from the Mogok Valley. This piece of jewellery sold for a whopping $30.42 million in 2015. Rubies are the world’s second rarest gemstones, after diamonds.

What determines the price of rubies?

As with diamonds and other coloured gemstones, the price per carat for rubies depends on the economy and the current market on the one hand, and the value of the ruby in question on the other. Rubies are valued according to the 4 Cs:

1. Carat

Good quality rubies weighing more than 1 carat are very scarce and the price of rubies therefore increases exponentially the greater the carat weight. However, as with other gemstones, carat weight is not what matters most. A ruby with a lower carat weight which does have a deep red colour, optimal clarity and excellent cut quality will be worth more than a ruby with a higher carat weight, but which falls short on the remaining 3 Cs.

2. Clarity

Rubies usually have inclusions. Totally pure rubies are therefore almost never found in practice. The value of the rubies is also affected by the inclusions, if they are strongly visible, the brightness will get weakened and the value will fall dramatically. Also, inclusions that reach the outer surface of the stone can cause fractures and thus affect the ruby’s durability.

Nevertheless, the presence of inclusions does not always have an adverse effect on a ruby’s value. Inclusions caused by minerals are sometimes called "needles" and, for example if there are inclusions of the mineral rutile, one can observe some interesting shapes created by the needles. This is also called “silk”. The presence of silk inclusions creates an optimal light reflection across the various facets. Occasionally those needles form a star effect which in the trade is called asterism and can sometimes be seen when the ruby has a cabochon cut.

3. Colour

Colour has a greater importance when when valuing rubies. Deep red rubies - neither too light nor too dark - are the most valuable. This type of red is often known in the jewellery trade as the red colour of pigeon blood. In other cases, if the colour is too dark, this could affect the brilliance and transparency of the stone but also, if it’s too light, the stone might even be considered as a pink sapphire in certain cases.

4. Cut

When it comes to cutting the rubies, the crystal lattice structure determines the most suitable cut for the stone. Popular cuts for rubies are oval, cabochon and cushion. As rough rubies are very expensive, cutters try to retain as much carat weight as possible when cutting.

Another factor that affects quality of the cut is the so-called optical phenomenon of different colours at different angles known as pleochroism. Rubies can appear red to purple from one angle and at the same time orange-red colour from another. Cutters try to minimise the orange-red colour effect caused by this optical phenomenon, although this is not always possible due to the risk of losing too much carat weight.

Why invest in rubies?

As mentioned above, the price per carat for rubies is quite high. After all, rubies are the second scarcest precious stone after diamonds. Rubies with exceptional qualities are therefore, very sought-after by collectors. Since rubies, like other gemstones, are a natural product whose source is finite, investing in rubies could be quite profitable in a long term. Investing in rubies is also a great way to complement your investment in diamonds.

Investing in rubies is different from investing in colourless diamonds. This is due to the fact that there is a high demand for colourless diamonds, as they are very commercial and they can be sold quickly. On the contrary, rubies are more of a niche market, and the returns depend strongly on selling them at the right time. To sell rubies at a profit, it is also recommended to call on experts who know this niche market inside out such as BNT Diamonds.

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Choosing between rubies, red diamonds or pink sapphires?

Red is the colour of love and passion and shares this symbolism with rubies, but rubies are not the only gemstone where red features in the leading role. Like rubies, sapphires are also a variety of the colourless mineral corundum. Classically, sapphires are blue but they also come in many other "fancy" colours including pink. As certain rubies come in a lighter shade of red tending towards pink, the distinction between rubies and pink sapphires is not always clear. Pink sapphires can of course also be very beautiful stones, but their cost per carat is much lower, hence they are not as good as an investment choice.

Red diamonds, on the other hand, are a much better investment. As well as the colourless variety, diamonds also come in many colours. These are known as "fancy colour" diamonds of which red diamonds are the scarcest. In the case of brown diamonds, the colour is caused by an irregular crystal lattice. You can read more about this in our article all about the difference between rubies and red diamonds.

Thinking about investing in rubies? Seek help from the experts at BNT Diamonds. Get in touch or speak directly to our team on +32 3 201 24 90.

Fabienne Rauw
About Fabienne Rauw
BNT Diamonds Antwerp

Fabienne, manager of the German market is able to guide every client with finding the right jewel. She takes care of most of the German orders, but also takes other task on her plate. Thanks to her six years of experience at BNT Diamonds she acquainted well with the product and the marketing around it. Her degree in PR ensures that BNT Diamonds is well presented across all media channels. For anyone looking into a new investment opportunity, Fabienne is the perfect guide in this process. No question will be left unanswered, and she will help you every step of the way.

With this article, BNT Diamonds strives to inform you thoroughly about investing in diamonds. No investment can be guaranteed to be without risk or fully according to your expectations. That is why we recommend to research the risks and aspects of investing in diamond properly to ensure that you make the right choice for your portfolio.