When is something valuable? When it is rare, beautiful and widely desired. Gemstones fulfil all these criteria. Nevertheless, different kinds of gemstone are worth different amounts.


Many people today believe that diamonds are THE most valuable gemstones of all, which can mostly be attributed to the influence of advertising and popular culture. Certainly, diamonds in the classic form of the brilliant-cut gemstone are beautiful and especially desired among women, but they are by no means among the rarest of stones.

In contrast, minerals such as roselite, mansfieldite or fingerite are so rare that they are often only to be found in one place on Earth. They are not, however, widely desired, with only a few mineral collectors or scientists showing any interest in them.

Whether or not a gemstone or a rare material is really valuable depends, therefore, not on its rarity but on the demand for it and its possible uses – especially in the form of jewellery.

The rarest gemstones that can also be used as jewellery stones are the following:

  • Grandidierite
  • Painite
  • Benitoite
  • Red beryl
  • Taaffeite
  • Poudretteite
  • Jeremejevite
  • Musgravite
  • Serendibite
  • Hibonite

If you are buying a gemstone as an investment, we do not generally recommend such extremely rare stones, as when the time for resale comes, one must first find a buyer who is familiar with such stones and is willing to pay the price you are expecting.

Therefore we recommend the established coloured gemstones, especially rubies, sapphires and emeralds. These should be of the highest possible quality and of a certain minimum size.
For centuries these gemstones have been in high demand; they are perceived as being extremely beautiful, are far rarer than diamonds and in investment quality regularly command high prices.

Should you wish to venture outside the “big 3 coloured gemstones” and invest in more exotic stones, high-quality tanzanites, tsavorites, tourmalines and alexandrites are also suitable.

Gelber Saphir

Should you wish to venture outside the “big 3 coloured gemstones” and invest in more exotic stones, high-quality tanzanites, tsavorites, tourmalines and alexandrites are also suitable. We are happy to provide individual advice.


So, what defines the concrete value of a ruby, sapphire or emerald? In contrast to precious metals, there is no “price per gramme” or “price per carat”. Every stone is different, every stone is individual.

The determining factors for the evaluation of a gemstone’s quality and thus its value are the so-called 4 Cs:

  • Carat (weight)
  • Colour
  • Clarity
  • Cut

The weight in carats of a gemstone can be directly correlated to its size, and for stones that are primarily bought as an investment the rule is: the bigger, the better.

The colour criteria are the actual colour hue of the stone, its saturation and its intensity. Depending on the gemstone, particular colours are especially desirable. “Pigeon blood” rubies are especially rare, in very high demand and thus exceedingly valuable. The case is similar for sapphires in the colours “padparadscha” or “cornflower blue”.
If the colour of a gemstone has been enhanced, for example by heat treatment, this has a negative effect on the value of the stone.

Clarity is important for transparent gemstones, with the obvious examples being rubies, sapphires and emeralds. Inclusions, fractures and crystallographic defects reduce the value of the stone. As exceptions prove the rule, we must here note that certain inclusions can make a gemstone unique and thus more valuable. The classic example of this is the star sapphire.

The art of cutting a stone concentrates on maximizing the impact of its natural aesthetic characteristics. As cutting styles are subject to the fashion of the times, investment stones should be cut in a style that is well-established for the relevant gemstone.


The source of a gemstone can have a considerable influence on its value. Whether justified or not, stones from certain regions and sources are especially sought-after.
Rubies from Burma, especially the region of Mogok, are considered the most beautiful in the world, with the result that they command higher prices than equivalent stones from other countries.
For sapphires the most highly-regarded source is Kashmir, which is again reflected in the prices that stones sourced here command.


Ensure that any gemstone you wish to buy as an investment has a certificate from an independent gemmological institute!

Checking the authenticity of a gemstone and correctly classifying it is a difficult task for the layman and sometimes even the expert and generally involves a huge amount of effort. This makes certificates from independent gemmological institutes extremely important. Gemstone certificates not only certify the authenticity of a stone, but also contain all the relevant information about it, such as its clarity, possible treatments, its source, etc.

Certificates from renowned institutes ensure security on the market. Gemstones without certificates can only be sold at discounted prices and are thus not suitable as investments.


The value of a particular gemstone is only partially related to its rarity. The price that it can command is far more a product of the demand for it on the marketplace and its certified quality.

Some gemstones do undergo certain variations in demand depending on the current fashion, but good gemstones have always been valuable and will remain so.

Since 1995 the market prices for naturally coloured, untreated gemstones have increased at least fourfold.

In times of war, gemstones have always found use as safe-haven currencies.

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Dr. Thomas Schröck
The Author:

Dr. Thomas Schröck

The founder and managing partner of THE NATURAL GEM has been active in international gemstone trading for 30 years. As a doctor of economics and a certified gemmologist in Switzerland, Germany and the USA, among other countries, he is one of Europe’s leading experts on naturally-coloured, untreated gemstones and investments in them.


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