Do Diamond

Do Diamond trades loose, certified diamonds from an office in Dietikon, on the western edge of the Zurich agglomeration rather than the city centre itself. There is no shop window and no drop-in counter. You get in touch by phone or email, and the site tells you plainly what happens next: they aim to be back in contact within a few hours of your enquiry, and from there you arrange a time to view stones in person at their office in the Limmat Tower, a 19th-floor address at Ueberlandstrasse 18. For anyone based in Zurich's western districts, or arriving from outside the city and not wanting to fight through Bahnhofstrasse traffic, that location is arguably more convenient than a maison boutique in the old town: Dietikon sits on the direct rail line into the city and back out again, so a viewing here does not require a special trip into the centre at all.

The business itself is small and specialist rather than a full jewelry house. It describes itself as a diamond trader with direct access to international diamond exchanges, sourcing stones from manufacturers rather than through a chain of middlemen, and it says it is entered in the Swiss commercial register as a diamond merchant. That framing matters for price: the site's own marketing line claims prices around 50 percent below typical retail or jeweler pricing for certified stones, on the logic that skipping a shop's rent, staff and margin layers leaves more of the price in the stone itself. That is the company's own claim rather than an independently audited figure, and it is worth treating it that way, but the underlying structure (a single office, appointment-only, no retail overhead) is exactly the kind of setup that makes such a claim plausible.

What you get

Every stone comes with paperwork from one of three internationally recognised labs: GIA, the Gemological Institute of America, HRD out of Antwerp, or IGI, the International Gemological Institute. The site is specific about the four factors that set a diamond's value, cut, carat, color and clarity, and treats the certificate as effectively a fifth, since it is what turns those four factors from a sales pitch into something you can check. Its own certificate page notes that a GIA-certified stone is generally considerably more valuable than an equivalent stone certified elsewhere, because GIA applies stricter grading standards, a distinction worth knowing before you compare two seemingly similar prices.

For authentication, Do Diamond explains laser inscription on its site: the certificate's report number gets etched onto the stone's girdle or table, invisible to the eye but readable under 10-15x magnification, and only the lab that issued the certificate is allowed to engrave it. Stones are also available sealed in a tamper-evident case that ties the physical diamond to its paperwork beyond doubt, though obviously you cannot handle a sealed stone loose before buying it. List prices, where published, are quoted net of Swiss VAT, so budget for that on top rather than assuming the sticker figure is what you pay at the till.

What stands out

What separates this from a purely transactional stone dealer is that the education pages read like they were written by someone who actually sells diamonds for a living, not copy pasted from a generic jewelry glossary. The carat-to-diameter chart on the site is a useful, concrete example: a one-carat round brilliant of standard proportions measures about 6.5 millimeters across, and a 10-carat stone, by their own chart, comes out around 13.9 millimeters, following the formula they publish (weight in carats equals the cube of the diameter in millimeters times 0.0037). Their buying-tips page goes further and gives an actual trade-off rather than a platitude: it argues you should weight color over clarity when choosing between two stones, because a color difference between grades D and H is visible to the naked eye, while a clarity difference between IF and VS2 is not, not without a 10x loupe. That is the kind of specific, checkable advice that separates a dealer who understands the stones from one reciting a script, and it lines up with what a good dealer in this category should be doing: showing trade-offs plainly rather than pushing whatever is in stock.

Alongside diamonds, the site also lists pearl jewelry, Tahiti, freshwater, Akoya and South Sea varieties, and offers custom-made pieces: solitaire rings, wedding and engagement rings, and earrings, built by their own goldsmiths from a photo or sketch you bring in. That custom route is clearly aimed at someone who already knows roughly what they want and needs it made rather than bought off a shelf.

What an international buyer in Zurich should know before booking

The site itself is German only. There is no language switcher and no English version of any page, including the contact page, so if German is not a language you are comfortable transacting in, it is worth asking upfront by email whether the appointment can be conducted in English rather than assuming it. Nothing on the site says either way, so this is a genuine unknown rather than a confirmed problem, and it is easy enough to clear up before you commit to a viewing.

A few other things a newcomer to Switzerland would want are simply not addressed on the site. There is no published turnaround time for a custom-made ring, no stated resizing policy, and no guidance on customs or export procedures if you buy here and later leave Switzerland with the piece. None of that means the answers are bad, only that they are not written down anywhere public, so they belong on your list of questions for the first call rather than something to assume either way.

On continuity, the trading address and mobile number on the current site match print advertisements for Do Diamond at the same Ueberlandstrasse 18 address going back to 2018, which is a reasonable amount of runway for a small appointment-only dealer with no shopfront to advertise from. The business also keeps an active Facebook page under the same name and address. Searches for signs of closure or financial trouble turned up nothing tied to this business specifically.

How it compares

Within this category, most dealers work the same way Do Diamond does: no shopfront, an office you visit by appointment, and a pitch built on cutting out retail markup. Do Diamond's version of that pitch leans on its western-Zurich location and its own directly-sourced stock rather than a famous cutting-house pedigree, which makes it a leaner, more local operation than a dealer routing every Zurich enquiry through an office in another city or country. The certification story here (three labs, laser inscription explained, a genuine steer on color versus clarity) covers the paperwork side of this category well, even though the business itself is a one-address operation rather than part of a larger group.

Verdict

For a buyer who wants a certified stone, understands they are dealing with a small, appointment-only trader rather than a boutique, and does not mind confirming a few practical details before booking, Do Diamond is a reasonable pick, especially if you are already on the western side of the Zurich area. The certification is real and cross-checkable against GIA, HRD or IGI, the educational content on the site suggests real expertise rather than filler, and the address has a track record going back to 2018 rather than being newly thrown up. The caveats are practical, not reputational: confirm the language of your appointment in advance, and ask directly about lead times, resizing and export before you commit to anything, since none of that is published. None of that is a reason to skip a dealer we list; it is simply the short list of questions worth asking on the first call.