Expert Interview about Jewellery and Gemstones

Marianne Rapp Ohmann, CEO of Rapp Auctions, in discussion with gemologist and mineralogist Dr. Fabian Schmitz and jewellery expert Gabriela Blöchlinger.

Diamond has been the king of the gemstones ever since the ancient Greeks and Egyptians. Its name stems from the Greek word “adamas”, which translates as “the unconquerable one”. This has to do with how immensely tough and durable it is. But diamonds are not just a extremely hard mineral, they are also a particularly valuable gemstone. They are crafted into pieces of jewellery or are sought after as individual stones and are traded as investments. Gemologist Dr. Fabian Schmitz and jewellery expert Gabriela Blöchlinger answer all manner of questions about the jewellery and gemstone market.

Dr. Schmitz, you are a mineralogist and gemologist and have worked as an expert at Rapp Auctions for more than two years now. How would you describe your day-to-day work? How does one become a mineralogist and gemologist?
Mineralogy is a varied degree. Currently, you can choose to specialise as a mineralogist when studying earth or materials sciences. Experience comes with time, but my interest wasn’t just sparked by the gemstones themselves, but also by the committed people who bring joy and life to this field. A gemologist mostly gains experience through research, trade and by visiting mines and deposits. There are gemological schools which teach the basics on this.

Dr. Schmitz, which gemstones are in particular demand at the moment?
The big three, ruby, sapphire and emerald are timeless and treasured in all sizes. Aquamarine in intense blue as well as tourmalines cut to optimise reflection of light are highly sought after from 10 carat and upwards. In general, there has been an increase in interest for all untreated coloured gemstones.

Herr Dr. Schmitz, Sie sind Mineraloge und Gemmologe und seit gut 2 Jahren für das Auktionshaus Rapp als Experte tätig. Wie muss man sich Ihren Berufsalltag vorstellen? Wie wird man Mineraloge und Gemmologe?
Die Mineralogie ist ein vielseitiger Studiengang. Aktuell kann sie als Spezialisierung im Bereich der Erdwissenschaften oder der Materialwissenschaften studiert werden. Die Erfahrung kommt über mehrere Jahre, doch das Interesse wurde nicht nur durch die Steine selbst geweckt, sondern die engagierten Menschen, die dieses Fachgebiet mit Leben füllen. Ein Gemmologe hat meist viel Erfahrung durch Untersuchungen, Handel und Reisen zu Minen und Lagerstätten gesammelt. Es gibt gemmologische Schulen, die dazu Grundlagen vermitteln.

Herr Dr. Schmitz, welche Edelsteine sind aktuell besonders gefragt?
Die “big three”, Rubin, Saphir, Smaragd in allen Grössen bleiben zeitlos beliebt. Aquamarine in intensivem Blau sowie Turmaline in reflexoptimierendem Schliff sind in Grössen ab 10 Karat begehrt. Generell kann man ein verstärktes Interesse an allen unbehandelten Farbsteinen sehen.

Schmuck – Auktionshaus Rapp – Zürich und Wil / St. Gallen, Schmuck über internationale Auktion verkaufen

Ceylon sapphire ring, white gold 18K. Sapphire (untreated), approx. 18.7 ct. Entouraged by 7 diamonds, 4 diamond drops, 20 brilliants. Ring size 52, 22,1 g. Lot from the next Rapp auction.

Schmuck – Auktionshaus Rapp – Zürich und Wil / St. Gallen, Schmuck über internationale Auktion verkaufen

Colombian emerald ring, platinum 950, emerald minor/insignificant oil, best colour and transparency of approx. 1.5 ct., 6 old-cut diamonds approx. 0.1 ct. Ring size 54, 2,9 g. Lot from the next Rapp auction.

Dr. Schmitz, why is it then that certain gemstones are so valuable?
It’s all because geologically-speaking, they are rarer. Some gemstones are more common, some are easier to mine, whilst others are more difficult to treat. Ultimately, the deciding factor regarding the relative rarity of a gemstone all comes down to what is known as the “Four C’s” – colour, clarity, cut and carat weight.

Ms Blöchlinger, which jewellery pieces do you sell at your auctions?
The jewellery must be well maintained, looked after and in pristine condition. There is particular demand for pieces from well-known jewellers and goldsmiths as well as renowned manufacturers. And as Dr. Schmitz mentioned, there is currently increased demand for all coloured gemstones.

Ms Blöchlinger, are there any trends on the jewellery market at the moment?
Jewellery from popular labels such as Cartier, Bulgari, Tiffany and so on are in particular demand at the moment, as are antique pieces in good condition from the Art Nouveau and Art Deco eras. There really are some delightful pieces of jewellery from these eras which have been delicately and masterfully crafted and which have once again come back to take centre stage.

Dr. Schmitz, how do you judge the quality of the stones? How do you estimate the value of a gemstone?
Once again it all comes down to the “Four C’s” – colour, clarity, cut and carat weight – which are looked at in quite an old-fashioned way. The colour must be intense and in most cases equally distributed across the stone. I always take a look at that with the naked eye, moving the stone under various sources of light. Doing a comparison with other marketable stones and their colours helps when estimating the value. The clarity is quantified according to the number of flaws for the respective type of gemstone by using a magnifying glass and to some extent, a microscope. The cut does not necessarily need to follow a specific, pre-defined pattern. However, the symmetry and polish of the facets is crucial for reflecting light well and for a good rendering of the colour. I am also able to calculate length and width ratios of facetted gemstones using measuring devices. The carat weight is measured using a carat scale or determined using formulas for fixed gemstones. To do this, I must have measured the fixed stone. Routinely, I have to check if it has been treated. And so the degree of “rarity” of the stone is determined according to all these criteria. The next, equally important step of the process is monitoring and classifying prices in the current market – that means, looking at what a similar stone currently costs across the market. And that’s how we get to the estimated value for auction.

Schmuck – Auktionshaus Rapp – Zürich und Wil / St. Gallen, Schmuck über internationale Auktion verkaufen

Santa Maria aquamarine diamond ring
of approx. 13 ct. in 3/4 frame setting entouraged by finest diamonds. (Lot at the next Rapp Auction).


Schmuck – Auktionshaus Rapp – Zürich und Wil / St. Gallen, Schmuck über internationale Auktion verkaufen

Emerald diamond stud earrings yellow gold 18K with 2 Colombian emeralds of approx. 3 ct. together, „Muzu-Green“, minor oil. (Lot at the next Rapp Auction).

Rubin Diamant Ring, Schmuck – Auktionshaus Rapp – Zürich und Wil / St. Gallen, Schmuck über internationale Auktion verkaufen

Burma ruby ring unheated, „vivid red“ of approx. 1.2 ct, entouraged by 12 diamonds. (Lots at the next Rapp Auction).

Schmuck – Auktionshaus Rapp – Zürich und Wil / St. Gallen, Schmuck über internationale Auktion verkaufen

Antique Burma ruby ring, „pigeon blood“ ruby untreated of approx. 3.5 ct. (Lot at the next Rapp Auction).

Ms Blöchlinger, how many jewellery pieces will be presented at the next Rapp auction? What are the highlights?
Around 800 auction lots that include jewellery will go under the hammer at our next auction. The selection is intentionally very diverse. I’m certain there will be particular interest in the rubies, sapphires, emeralds and diamonds which are large and untreated, where the quality of the stones is definitely the focus.

Dr. Schmitz, why are signed jewellery pieces such as those from Tiffany, Boucheron, Harry Winston and so on so popular?
Well-known brands know how to put a new spin on classic ideas and don’t just follow trends, but define them. Traditional brands do this through their experience with customers, discussion and by careful judgement of what is “being hyped”.

Ms Blöchlinger, do you sell only very expensive jewellery pieces? From which scale can I sell jewellery at your auctions?

We are going to hold two Jewellery auctions: The lower-priced pieces with a starting value of CHF 500 will be auctioned off at the online only auction. As the name suggests, it is only possible to participate in this auction online. The more valuable jewellery pieces valued at CHF 1200 to tens of thousands will go under the hammer at the hall auction. Customers may place bids either in the auction hall, online or via telephone.

Ms Blöchlinger, when is it worthwhile selling jewellery at auction with an auction house such as Rapp?

We always recommend selling at auction when we see clear added value. Jewellery is personal and tastes are very different. Many of our international customers adore jewellery created by Swiss jewellers, which of course has a positive impact on the price. Time and time again, we are pleasantly surprised with auction prices that greatly surpass our appraisals. In those cases, there are generally numerous persons who are desperate to bring a piece home and that drives the price higher and higher. And at the end of the day, that is exactly what is appealing about selling at auction.

Ms Blöchlinger, Dr. Schmitz, thank you very much for partaking in this interview. I very much look forward to the next jewellery auction at Rapp Auctions which will take place during the grand auction week from 2 – 7 May 2022.

Would you like to participate in the upcoming Rapp auction with jewellery, watches, stamps, coins, porcelain or designer handbags? Then reserve an appointment at our next Expert Day. We can also visit you at home if you have large items to sell.
The deadline for consignments is 5 March 2022.



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