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Which gemstones are particularly worthwhile as an investment? Regardless of trends, there are some minerals for which a continuous price increase over several years can be assumed. These include, of course, the best-known colored gems – ruby, sapphire and emerald –, which are also known to laymen, but also stones such as alexandrite and tanzanite.


In several other articles, we describe in detail what is particularly important to consider when investing in gemstones, give an overview of why gemstones are particularly suitable for an investment and how to compile a gemstone portfolio.

The most important information: As an investment, almost all gemstones are suitable only as untreated, but cut natural-colored stones. In addition to beauty, rarity, cut, etc., the reputation of a mineral is also decisive for it to be considered for investment. Colored gemstones are interesting for an investment from a weight of one carat (1 ct. = 0.2 g. ), diamonds already from 0.5 ct. Investment gemstones require an internationally recognized certificate from a gemological institute. As a rule of thumb, 10 to 20% of liquid assets should be invested in gemstones and a long investment horizon of five or more years should be considered.

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


Diamonds are the most popular and well-known gemstones, so one would expect them to appear in a list of the top 10 investment gemstones right at the beginning. But in recent years, it has been shown that economic crises cause diamonds to drop in value – for example, the value dropped during and after the 2008 financial crisis and also during the COVID-19 crisis. However, diamonds are well suited as an investment if the investment horizon exceeds 20 years.



As expected, the first places are occupied by ruby, sapphire and emerald. It is difficult to determine a ranking among these three. Your own preferences and your existing portfolio have to be taken into consideration to choose the right investment gems for you.

1. Ruby

Rubies are the hardest mineral in the world after diamonds and much rarer than diamonds. It is the red variety of corundum and the most sought-after rubies are pigeon blood red ones. As an investment they are interesting from a weight of 1 ct. up. Clear, red stones with 5 ct. and more are absolute rarities. A price increase of 5-8% on average per year can be expected.

2. Sapphire

Sapphires come in many different colors, the best known being blue sapphires. Deep blue sapphires have the highest value in trade, most of these come from the Indian Kashmir region. Another sought-after variety is the Padparadscha sapphire, which has the orange-pink coloring of lotus blossoms caused by traces of iron and chromium in the mineral. As with rubies, stones with one 1 ct. or more are interesting as an investment, but the current popularity of the respective color variety also has a strong effect on the price development.

3. Emerald

Emerald is the green variety of beryl. Deep green, clear specimens are particularly sought after. A special cut was developed for emeralds: The so-called emerald cut looks like a rectangle with beveled corners when viewed from above. Again, clear stones with a beautiful color saturation weighing 1 ct. or more should be considered for an investment portfolio.



This list is not an explicit ranking: With all these seven gemstones a stable increase in value over several years can be assumed. For valuation, selection and purchase you should definitely refer to expert opinions, since these are very rare stones and some of them are still little known on the general market.


Tourmalines exist in all colors of the rainbow. The name “Paraiba Tourmaline” was originally coined for all intensely turquoise-blue gems that came from mines in the state of the same name in Brazil. Today also tourmalines from Mozambique and Nigeria get the designation “Paraiba” in gemological certificates, if they meet the turquoise or blue notes in color and the concentrations of copper and manganese. From an investor’s point of view tourmalines are especially interesting if they show strong colors, are eye-clean and have a size of 5 ct. and more. Paraiba tourmaline is suitable for sizes as small as 1 carat.

5. Aquamarine

The name aquamarine comes from Latin – “aqua marina” means “sea water”. Aquamarine is the blue variety of beryl – emerald is the green one. “Santa Maria aquamarines”, which are named after the mine of the same name and are deep blue, are of particularly high quality. In reference to this, there is also the designation “Santa Maria Africana” for stones from a mine in Mozambique, which strongly resemble the Brazilian ones. The intense blue, which is also sought after for gemstones, is very rare in naturally occurring stones and is often produced for trade by firing the gemstones.

6. Alexandrite

Alexandrite was discovered in the 19th century and named after Tsar Alexander II. This mineral is a variety of chrysoberyl and with a Mohs hardness of 8.5 it is the third hardest mineral in the world. A special feature of alexandrite is the color change between red and blue depending on the quality of the light. For investors, gemstones with 1 ct. or more are interesting.

7. Tanzanites

Tanzanites come from a finding area in Tanzania which is only a few square kilometers large. They are deep blue stones, and almost all stones available on the market are fired to make brown and violet tones disappear. The export of the stones – especially larger stones over 5 ct. – is still subject to strong restrictions, which is why those are very popular with investors. Tanzanite is one of the few gemstones where heating does not lead to cheaper price.

8. Spinel

As mineralogy was only able to distinguish between red spinels from rubies from the early 1800s on, red spinel has only been recognized as an interesting gemstone sine then. Most in demand on the world market are bright red, clear stones; pink stones are now also very popular. Red spinels are still cheaper than rubies, but they have a strong potential for price increase, because especially high-quality stones weighing more than 10 ct. are very rare.

9. Peridot

Peridot is a particularly pure variety of olivine. It occurs only in green, from light green to olive and dark green. Unlike other gemstones, peridot is not subjected to treatments such as irradiation or burning, and the green coloration is always natural. Compared to other green gemstones like emeralds, peridot is still relatively inexpensive, but for high quality stones, prices have been rising in recent years.

10. Colored “fancy” diamonds

The fact that diamonds exist in different colors is often unknown to laymen. But at auctions, colored diamonds, also called “fancy diamonds”, are regularly among the most expensive stones. Pink, orange and blue diamonds fetch record prices in the millions – currently, the most expensive gem ever sold is also a pink diamond, the so-called “Pink Star” (which changed hands for $71.2 billion in 2017). Colored diamonds therefore represent an interesting investment starting from a size of 0.5 ct.

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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