June 28, 2024

Are the Rarest Gemstones the Most Expensive, Valuable or Precious?

What is the rarest gemstone?

People have always been drawn to the magic of gemstones - the rarer, more expensive or more valuable the more alluring. From larger-than-life Diamonds to vibrant emeralds, these natural wonders are often regarded as symbols of wealth, status, and beauty. However, it still poses some questions, such as: What is the rarest gemstone? What is the most expensive gemstone? And what is most precious or valuable? To provide some answers, we must first understand what defines rarity, value, and preciousness in the context of gemstones, as one does not always directly correlate with the other. 

Defining rarity, value and preciousness

What makes a gemstone rare?

The main factors in determining a gemstone’s rarity are geological, in other words, the scarcity of the materials that make up the gemstone and therefore the specific, limited places where it can be mined or sourced. Mostly, the rarer the materials and more restricted the sources, the rarer the gemstone, but not in every case. Take for example Painite - named after its discoverer Arthur C.D. Pain - it is the rarest gemstone mineral in the world. Of the more than 1000 ever found, only a handful are of gemstone quality, but it doesn’t necessarily fetch a higher price than pure, coloured Diamonds.

For instance, Quartzes like Amethyst, although beautiful to behold, are comparatively common to find, as Quartz forms a significant portion of the Earth's crust. Diamonds on the other hand are found in many identified Kimberlite pipes and deposits worldwide, however, only a fraction of these yield Diamonds and an even smaller fraction of those are of appropriate quality. As an illustration of this, there are roughly 7000 kimberlite pipes identified globally but only about 1,000 of these pipes contain Diamonds, and fewer than 100 of these are economically viable for mining.

To put that into the context of diamond yield, an economically viable deposit typically results in around 25 carats of Diamonds per 100 tonnes of ore. Of these, approximately 20% (or 5 carats) may be of gem quality. For reference, 1 carat equals only 0.2 grams, so you can see how Diamonds could be considered abundant from one perspective, but still rare when it comes to Diamonds used for jewellery. 

Another rare example is Tsavorite Garnet, which is only found in Kenya and Tanzania. Similarly, Paraíba Tourmaline is only found in one mine in Brazil and has now nearly been exhausted, making it more and more valuable as supplies decrease. Tourmaline from Mozambique is very close in appearance and less expensive and therefore doesn’t have that exclusivity. Additionally, pink Diamonds from the Argyle mine in Australia are becoming increasingly rare since the mine ceased operations in 2020. 

Some gemstones like Cobalt Blue Spinel and Red Beryl are even rarer and more expensive in pounds per carat than most Diamonds. Even though Red Beryl is not suitable for jewellery because the manganese in its structure makes it very brittle, many gem collectors who own Red Beryl will not sell it because of its inherent value.

Large green Diamonds, like the Dresden Green Diamond, are extremely uncommon and prized for their optical effects. Just like Star Sapphire and Catseye Chrysoberyl, their unique appearance makes them very rare. 

Factors influencing rarity

As well as geological considerations, there are some other factors that influence the rarity of gemstones.

Source: Burmese Rubies, for example, are incredibly rare because of the country’s political unrest and the mines being nearly exhausted. Political instability, geographic location, trade restrictions, and environmental regulations can further limit the availability of certain gemstones.

Historically, the locations that fetch the highest price per carat for gemstones are:

  • Colombia - Emeralds
  • Kashmir - Ruby and Sapphire
  • Myanmar (Burma) - Ruby and Sapphire
  • Golconda - Diamond, Colourless type IIA white Diamonds and blue Diamonds
  • The Argyle Mine - Pink Diamond

Trends and Consumer Preferences: A gemstone’s rarity, perceived value, demand and supply are all affected by fashion trends and preferences. Case in point, Princess Diana’s engagement ring caused a rise in popularity in royal blue Sapphire engagement rings and specifically in cluster-style rings, and Blake Lively’s oval-shaped Diamond solitaire engagement ring also drove up demand.

What makes a gemstone valuable, expensive or precious?

Rarity itself is not the only aspect to determine a gemstone’s value and preciousness. The "Four Cs" (Cut, Colour, Clarity, and Carat weight) play a pivotal role in this.

Cut: This refers to how well a gemstone has been shaped and faceted to enhance its brilliance and sparkle. The cut is crucial as it affects a gemstone's overall appearance and value, and sometimes even more than its colour or clarity.

Colour: White diamonds use the D-Z scale, where "D" represents the most colourless and thus the most rare and expensive Diamonds. There’s a drastic decrease in value after “M” generally Closer to “Z” means more nitrogen in the crystal lattice causing a yellow colour. Blue, pink, red and green are exceptions as they are rarer which increases the value. Diamonds can also be brown or grey. For other gemstones, the more vibrant and pure the better.

Clarity: Generally the more clarity a gemstone has the more expensive it is. Clarity measures inclusions and blemishes, so the fewer the inclusions and the higher the clarity, the more valuable the gemstone. However, some gemstones, like Emeralds, are known for having inclusions, often referred to as "jardin" (French for garden).

Carat weight: Carat weight measures the size of the gemstone. One carat equals 0.2 grams. Larger gemstones are rarer and thus more valuable, so a 2-carat diamond will be significantly more expensive per carat than a 1-carat diamond of the same quality.

Then there are factors like quality, historical or cultural significance, and provenance. Quality denotes a stone’s durability, brilliance, and lack of inclusions. Certain gemstones are more valuable in different parts of the world, such as Jade which is highly valued in China but not in the West (which is why the most significant Jade auctions take place in Hong Kong). Pearls are ordinarily not exceptionally expensive, but Marie Antoinette’s brooch auctioned for millions of pounds due to its provenance.

The rarest, most valuable, expensive and precious gemstones ranked

Below we’ve ranked a list of gemstones by value, along with the factors making them the most valuable, precious or expensive:

  1. Coloured Diamonds
    • Description: Includes rare hues like pink, blue and green.
    • Value Range: £8,000 to $800,000+ per carat.
    • Factors: Intensity of colour, carat weight and clarity.
  2. White Diamond
    • Description: Known for their exceptional hardness and brilliance.
    • Value range: £1,500 to £20,000+ per carat.
    • Factors: Colourless quality, high clarity, excellent cut, and substantial carat weight.
  3. Ruby
    • Description: Valued for their rich red colour and historical significance.
    • Value Range: £800 to £8,000+ per carat.
    • Factors: Burmese in origin, colour intensity, carat weight, clarity and cut quality.
  4. Emerald
    • Description: Renowned for their deep green colour and rarity.
    • Value range: £500 to £8,000+ per carat.
    • Factors: High clarity, minimal oil treatment, large carat weight, and Colombian in origin.
  5. Paraíba Tourmaline
    • Description: Famous for their neon blue hue.
    • Value Range: £8,000 to £40,000+ per carat.
    • Factors: Origin from Paraíba, Brazil, colour intensity, carat weight and clarity.
  6. Sapphire
    • Description: Known for their vivid blue colour.
    • Value Range: £400 to £6,500+ per carat.
    • Factors: Kashmir or Sri Lankan in origin, colour intensity, carat weight, clarity and cut quality.

Are the rarest gemstones the most valuable, expensive or precious?

Generally speaking, a rarer gemstone will fetch a higher value, but in other cases, cultural and historical significance plays a bigger role in determining the overall value and preciousness. So while some Diamonds are very rare, their value can vary significantly based on the Four Cs, or as with Jade’s cultural significance in China, the value is raised there. Of course, there are exceptions to the rule such as Red Beryl, which is extremely rare but not suitable for jewellery.

The answer to the question of whether the rarest gemstones are also the most valuable, expensive or precious is therefore not always so straightforward. Asking “what is the rarest gemstone” will not always give you the answer of the most expensive one, and vice versa. For the most part, rarity is perceived by the wearer, ultimately making the value a more personal factor. 

The quality of the gemstone, cultural significance, and market demand are equally important factors. So while the rarest gemstones often command higher prices, the most valuable and precious gemstones are those that combine rarity with exceptional quality and cultural significance. 

Thankfully, there are gemstones and Diamonds to suit everyone’s tastes and intentions, and we at Blackacre are proud to be able to guide you in your choice when buying a bespoke classic diamond engagement ring or coloured stone engagement ring. If you need help in choosing future heirlooms or meaningful pieces, please get in touch and we’ll gladly discuss your needs. 

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