Gemstones are formed in the earth, therefore they have something mystical and enigmatic about them.
For thousands of years collectors have been fascinated by the radiance of a ruby seen in daylight or candlelight,
by the deep blue light reflected from a sapphirine or the intense green of an emerald.

What is it that makes a gemstone so special? The answer is simple: its rarity and desirability.
The rarer and more coveted something is, the higher its price will be, whether it is jewellery,
worn as an expression of sentiment, or as a mere store of value.

Especially in times of economic uncertainty gemstones can be a lasting long term investment.
“Natural gem auctions“ (NGA) offers a transparent and reliable occasion
to purchase gemstones by auction for a reasonable price.




“Natural gem auctions“ – founded in September 2017 – is Europe’s first auction house that is exclusively dealing with certified gemstones of high quality.

The idea to establish an auction house is rooted in a deep affection towards gemstones and the profound knowledge of alternative types of investment. Over the past years Emanuele Bertolaso and Thomas Schröck have established themselves as specialists in this very field.

Each of the gemstones and diamonds offered in the auction have a certificate issued by one of the worlds most renowned gemological institutes. These certificates verify the originality, certain attributes as well as the provenance of each individual stone.

Thanks to its international relations with the best gemological institutes, its global clientele and the recognition of international market for gemstones, NGA guarantees excellent advice and guidance.




Dr. Thomas Schröck

The educated business economist developed a great interest in gemstones early in his life. Twenty years of age he founded a jeweller’s shop and became one of the youngest professionals in this métier. For the purpose of investment he deepened his knowledge about natural-coloured gemstones and diamonds. In fall 2017 his first book “Edelsteine als Investment“ will be published by “Gewinn-Verlag“.

Mag. Emanuele Bertolaso

The born Italian focussed his professional career on financial consulting with a particular interest in alternative investments. Alongside his work in the field of art his path led him to trading precious gemstones.
Bertolaso preferably works with private banking houses who operate internationally, as well as institutional and private clients worldwide.




Our experts will show you the objects of exposition and gladly answer your questions. Reserved slots for groups and private inspections are possible upon consultation. We are looking forward to your inquiry!



Private Sales

We handle the sales of your gemstones on a confidential
and professional level as we transfer them to potential buyers discreetly.

You will benefit from our profound knowledge of the international market
for gemstones and our global clientele for natural gems of high quality.

Our evaluation and expertise allow us to achieve the best transaction
of your object as well as the highest price possible.

For ambitious buyers our private sales offer the ideal occasion to
acquire some of the rarest and most treasured gemstones in a discreet way.