Direct-source stones
Every chalcedony, aquamarine, and moonstone we use is sourced directly from lapidaries in Minas Gerais and from a small family cutter in Alentejo. No middlemen, no mystery origins.
Our products
Why the stone matters here
Hand-set in Lisbon
All settings are done by hand in our Mouraria atelier. We do not outsource the setting work. The bench where the stone with the metal is ours, and we know every piece that leaves it.
Small-batch production
We make between four and twelve of any given design. When a run sells out, it is retired. We do not reprint a design just because it was popular.
News & Announcements
News & Announcements
2026-04-10
What is chalcedony and why does it wear so well?
Most people who come into the atelier have heard the word chalcedony but are not entirely sure what it is. That is fair. It sits in a confusing part of the gemstone world, related to agate and jasper, sometimes sold under other names, often misidentified. This is a plain account of what chalcedony actually is, how it forms, and why we have built an entire studio around it.
Read more →2026-02-20
How a bespoke jewellery commission actually works
The word bespoke gets used loosely in jewellery. Sometimes it means choosing a stone from a pre-set menu. Sometimes it means picking a metal colour. At Authentic Chalcedony, bespoke means we design the piece from a blank page, with your stone, your brief, and your approval at each stage. Here is what that process actually looks like.
Read more →2026-01-08
How to care for sterling silver jewellery at home
Sterling silver tarnishes. This is not a flaw in the metal; it is a chemical reaction between the silver and sulphur compounds in the air, and it happens to all sterling regardless of quality. The question is how to manage it without damaging the stone it is set with, because most cleaning methods that work well on silver are too harsh for chalcedony, moonstone, or labradorite.
Read more →The person
Who you are buying from
Founder, Established since 2017
Mariana Fonseca
Mariana Fonseca trained as a goldsmith's apprentice under Jorge Melo at Ourivesaria Melo in Porto, where she spent eight years learning to set stones before she could set her own agenda. She moved to Lisbon in 2015, spent a year buying loose chalcedony at the Feira da Ladra, and opened Authentic Chalcedony in 2017 with a table at the Mercado de Arroios and nine rings. She reads lapidary journals on Sunday mornings and keeps a small notebook of stone sketches that she has never shown anyone. Her benchmark for a finished piece is whether she would wear it on a long walk.
FAQ
Common questions
Q01
How do I start a bespoke commission?
The easiest way is to send us an email or fill in the enquiry form with a rough description of what you have in mind. We will reply within two working days to arrange a consultation, either in person at the atelier on Rua dos Lagares or by video call. We do not require you to have a finished idea. A stone you love, a colour, a memory of a piece you once saw, all of that is enough to begin.
Q02
What if the design needs to change partway through?
It happens, and it is fine. We build one revision round into every commission. If the route changes significantly after the design is approved and work has begun, we will talk through what is involved and agree on any additional cost before we continue. We do not surprise people with invoices.
Q03
How long does a bespoke piece take?
Six to ten weeks is the honest range. Stone sourcing is the variable. If you are using a stone you already own, or choosing from what we have in the atelier, the timeline is closer to five or six weeks. If we need to source a specific cut or colour from Brazil, add two to three weeks for shipping and customs.
Q04
Do you ship outside Portugal?
Yes. We ship across the EU for a flat €8, tracked and insured. For the UK, Switzerland, and non-EU countries, shipping is €18 and we use DHL Express with full insurance. All pieces are packed in a rigid box with a hallmark certificate. We do not ship uninsured.
Q05
Can I visit the atelier without an appointment?
We are open to visitors on Thursdays and Fridays, 10h to 17h, but we strongly prefer appointments because we are often mid-set and cannot give you proper attention otherwise. Email us or use the contact form and we will find a time. The first Monday of each month the atelier is closed for cleaning and stone inventory.