Last updated: August 2026
Tatiana Marques Jewelry believes that the value of fine jewelry should be supported not only by craftsmanship and design, but also by clear information about the materials used and, where applicable, appropriate official or independent documentation.
This page explains the distinction between Portuguese precious metal hallmarking, the Tatiana Marques Jewelry Certificate of Authenticity and independent gemological documentation.
These forms of documentation serve different purposes and should not be confused with one another.
1. PRECIOUS METAL HALLMARKING IN PORTUGAL
Precious metal jewelry placed on the Portuguese market is subject to the Portuguese legal regime governing jewelry and assay offices.
Portuguese Assay Offices, known as Contrastarias, are official and technical services integrated within the Imprensa Nacional Casa da Moeda, INCM.
They are responsible for assaying and marking precious metal articles and for applying official marks that guarantee the legally recognised metal and fineness of qualifying articles.
There are currently two Portuguese Assay Offices:
Lisbon Assay Office
Porto Assay Office, including the Gondomar branch.
Operators may use either Assay Office regardless of their geographical location.
2. WHAT IS A HALLMARK?
A hallmark is an official mark associated with the legal control of precious metal articles.
Under the Portuguese regime, an Assay Office mark identifies the official Assay Office responsible for marking and, in general, indicates the precious metal and legal fineness concerned.
The mark also attests that the article meets the technical requirements applicable to its lawful introduction onto the market.
A hallmark is therefore not simply decorative branding.
It is part of an official precious metal control system intended to provide assurance concerning the metal and fineness of qualifying jewelry.
3. WHAT DOES THE ASSAY OFFICE VERIFY?
The Portuguese Assay Offices are responsible for independently testing and marking precious metal articles.
Their statutory mission includes guaranteeing the type and legal fineness of precious metal articles and promoting transparency in commercial transactions and consumer protection.
The Assay Office does not certify the artistic quality, market value, originality or gemstone quality of the finished jewel merely by applying a precious metal hallmark.
Those matters are distinct.
4. PRECIOUS METALS COVERED
The Portuguese precious metals regime recognises precious metals including:
Platinum
Gold
Palladium
Silver
The legal fineness of an article is expressed in parts per thousand.
For example, an 18k gold alloy corresponds to a fineness of 750 parts of gold per 1,000 parts of alloy.
The hallmarking system concerns the precious metal content of the article and should not be confused with gemstone grading or independent gemological certification.
5. TATIANA MARQUES JEWELRY GOLD
The principal gold standard used by Tatiana Marques Jewelry is 18k gold, subject to the specifications of each individual piece.
Other finenesses may be used where appropriate and expressly agreed for a particular project.
Where a different gold fineness is selected, that information will be communicated as part of the product or project specifications.
The gold colour, such as yellow, white, rose, red or another agreed alloy colour, is a separate characteristic from gold fineness.
6. RESPONSIBILITY MARK
Precious metal articles may also bear a responsibility mark, sometimes referred to in Portuguese as a marca de responsabilidade.
Under Portuguese law, this mark identifies the economic operator responsible for introducing the precious metal article onto the market.
The responsibility mark and the Assay Office mark perform different functions.
The responsibility mark identifies the responsible operator.
The Assay Office mark provides the official guarantee relating to the precious metal and legal fineness.
7. HOW HALLMARKS MAY BE APPLIED
Portuguese law permits approved precious metal marks to be applied using different technical methods.
These may include:
- traditional punching;
- laser marking;
- approved labels;
- or another method accepted by the Assay Office.
The appropriate method depends on the article, its construction and the technical requirements applicable to marking.
For delicate, small or technically sensitive pieces, the marking method may therefore differ from what a client might traditionally expect from a visible punched hallmark.
8. SMALL ARTICLES AND LEGAL EXEMPTIONS
Not every precious metal article is necessarily required to carry an Assay Office mark.
Under the current Portuguese regime, qualifying articles may be exempt from the Assay Office mark where their weight does not exceed certain statutory thresholds.
At present, articles containing platinum or gold with a relevant weight of 0.5 grams or less, and silver articles with a relevant weight of 2 grams or less, may fall within this exemption, subject to the other applicable legal requirements.
An absence of an Assay Office mark on a qualifying exempt article does not therefore automatically mean that the article is unlawful or that the stated metal is incorrect.
9. MARKING AND THE DESIGN OF A PIECE
The need for legally required marking is considered as part of the technical development of a piece.
Where possible, marks are positioned so that they remain legible while respecting the design and structural integrity of the jewelry.
The precise position and appearance of a hallmark may vary depending on:
the size of the piece;
construction;
available surface;
design;
metal;
and marking method.
Hallmarks are functional legal marks and slight differences in their placement or appearance are not defects in handcrafted jewelry.
10. TATIANA MARQUES JEWELRY CERTIFICATE OF AUTHENTICITY
Tatiana Marques Jewelry may supply a Certificate of Authenticity with a finished piece.
The Certificate of Authenticity is issued by Tatiana Marques Jewelry and forms part of the brand's documentation of the jewel.
Depending on the piece, it may record information such as:
Piece name or reference
Jewelry category
Metal and fineness
Gold colour
Gemstones
Dimensions
Final weight
Craftsmanship or relevant techniques
Completion date
Certificate reference
Other relevant specifications
The exact information included depends on the individual piece.
11. WHAT THE CERTIFICATE OF AUTHENTICITY MEANS
The Tatiana Marques Jewelry Certificate of Authenticity records the specifications and identity of a Tatiana Marques Jewelry creation.
It is intended to provide the client with a permanent record of the piece as created and supplied by the atelier.
It may also support future:
maintenance;
repair;
identification;
service history;
insurance documentation;
family records;
or provenance associated with the Tatiana Marques Jewelry creation.
12. WHAT THE CERTIFICATE OF AUTHENTICITY IS NOT
The Tatiana Marques Jewelry Certificate of Authenticity is not the same as:
an official Portuguese Assay Office hallmark;
an independent gemological laboratory report;
an independent valuation;
an insurance appraisal;
or a guarantee of future resale value.
The Certificate is issued by Tatiana Marques Jewelry as documentation of the jewel and its known specifications.
Official precious metal verification and independent gemstone analysis are separate processes.
13. FINAL WEIGHT
Where final weight is included on the Certificate of Authenticity, it records the weight of the completed piece at the relevant stage of documentation.
A final jewelry weight is distinct from any estimated weight included in an earlier design or proposal.
For pieces incorporating gemstones, findings or other components, the final gross weight may include all materials forming part of the completed piece unless specifically stated otherwise.
14. CLIENT OWNED GOLD
Where a jewel incorporates client owned gold, the Certificate of Authenticity may record that client supplied material was used where relevant to the project.
This does not mean that the entire final piece consists solely of the original client gold.
Technical production may require refining, alloy adjustment, addition of new metal or other processes necessary to achieve the intended fineness, colour, weight and structural quality.
The more detailed custody and material accounting rules are set out in the Terms & Conditions and, where applicable, the Client Gold Intake and Custody Form.
15. CLIENT OWNED GEMSTONES
Where client owned gemstones are incorporated into a new Tatiana Marques Jewelry creation, the Certificate may record the stones used based on the available information.
Unless a stone has been independently assessed or laboratory documented, a description recorded by Tatiana Marques Jewelry does not automatically constitute an independent gemological determination.
For example, recording a client supplied gemstone as a stone described or reasonably identified as a particular gem does not transform the Certificate of Authenticity into a laboratory report.
16. GEMSTONE DOCUMENTATION
Some gemstones may be accompanied by independent documentation.
This depends on factors including:
the type of gemstone;
size;
value;
commercial relevance;
supplier;
availability;
project requirements;
and the client's specific request.
Not every gemstone requires or is normally supplied with an individual independent laboratory report.
17. CERTIFIED DIAMONDS
For certain diamonds, particularly stones of significant size, value or specification, Tatiana Marques Jewelry may source a diamond that already has an independent grading report from a recognised gemological laboratory.
Depending on the laboratory and report, diamond documentation may record characteristics such as:
carat weight;
colour;
clarity;
cut;
measurements;
polish;
symmetry;
fluorescence;
and an identifying report number.
The exact information varies according to the laboratory and type of report.
18. COLOURED GEMSTONES
Certain coloured gemstones may also be supplied with independent gemological documentation where appropriate.
Depending on the stone and laboratory, a report may address matters such as:
identity;
weight;
dimensions;
known treatments;
and, for certain stones and report types, geographical origin.
Not every coloured gemstone is routinely submitted for independent laboratory analysis.
The cost and commercial relevance of laboratory documentation are considered in proportion to the gemstone and project.
19. GEMSTONE ORIGIN
The word origin can have different meanings in jewelry.
It may refer to whether a gemstone is:
natural;
laboratory grown;
or another recognised material category.
For certain natural gemstones, an independent laboratory may also offer an opinion regarding geographical origin.
These are different questions.
A statement that a gemstone is natural does not automatically constitute a determination of geographical origin.
Where geographical origin is material to a project, it should be expressly discussed and independently documented where appropriate.
20. NATURAL AND LABORATORY GROWN GEMSTONES
Where laboratory grown gemstones are used, their origin as laboratory grown will be disclosed.
A laboratory grown diamond or gemstone may also have independent gemological documentation where appropriate.
The existence of a grading report does not mean that a gemstone is natural.
The report itself should identify the nature of the material according to the terminology and findings of the issuing laboratory.
21. GEMSTONE TREATMENTS
Certain gemstones may undergo treatments commonly used within the jewelry industry.
Where treatment information is known and materially relevant to the project, care, value or description of the stone, it will be disclosed where appropriate and legally required.
Independent gemological laboratories may provide information concerning detected treatments within the scope and limitations of the particular report.
Tatiana Marques Jewelry cannot independently guarantee that an externally supplied or client owned gemstone has never been treated where its history is unknown and no appropriate laboratory analysis is available.
22. INDEPENDENT GEMOLOGICAL REPORTS
An independent gemological report is issued by the laboratory that examined the gemstone.
Tatiana Marques Jewelry does not control the laboratory's:
grading methodology;
terminology;
opinion;
scope of analysis;
or technical conclusions.
Where a stone is supplied with such documentation, Tatiana Marques Jewelry will represent that documentation accurately.
The independent report remains subject to the issuing laboratory's own terms, methodology and limitations.
23. REQUESTING A CERTIFIED GEMSTONE
If a client specifically requires a gemstone with independent laboratory documentation, this should be communicated before the gemstone is sourced or purchased.
A request for independent documentation may affect:
available gemstone options;
price;
sourcing time;
supplier choice;
and project timeline.
Where certification is an essential requirement, it should form part of the agreed project specification.
24. REPORT NUMBERS AND IDENTIFICATION
Where a gemstone is accompanied by an independent report, the report number should correspond to the documentation supplied with that stone.
Some diamonds may also carry a microscopic laser inscription linked to their grading report where provided by the relevant laboratory or supplier.
The presence or absence of such inscription depends on the stone and laboratory service and should not be assumed unless expressly confirmed.
25. KEEPING GEMSTONE DOCUMENTATION
Clients should retain any independent gemstone report supplied with their jewelry.
Where possible, the report should be stored separately from the jewelry itself.
This reduces the risk of both the jewel and its documentation being lost together.
Independent laboratory documentation may be useful for future identification, insurance, resale discussions or reassessment of a gemstone.
26. LOST GEMOLOGICAL REPORTS
If an independent laboratory report is lost, Tatiana Marques Jewelry may be able to assist in identifying the report reference where that information remains in the project records.
Whether a replacement report or duplicate documentation can be obtained depends on the issuing laboratory and the information available.
A new physical inspection or laboratory submission may sometimes be necessary.
27. LOST TATIANA MARQUES JEWELRY CERTIFICATE
Where a Tatiana Marques Jewelry Certificate of Authenticity is lost, the client may contact the atelier.
Where the piece and corresponding project records can be reliably identified, Tatiana Marques Jewelry may be able to provide replacement or updated documentation.
The atelier may request:
photographs;
the original purchaser's details;
piece reference;
proof of purchase;
physical inspection;
or other information reasonably necessary to verify the piece.
Issuing replacement documentation is subject to sufficient records and verification.
28. CERTIFICATE TRANSFER AND SECONDARY OWNERSHIP
A Tatiana Marques Jewelry Certificate of Authenticity relates to the identified jewelry piece, not exclusively to the original owner.
Where a genuine Tatiana Marques Jewelry piece changes ownership, its original Certificate of Authenticity should ideally remain with the jewel.
Tatiana Marques Jewelry does not automatically verify the circumstances of a private resale or transfer of ownership.
Where a subsequent owner requests authentication or documentation, Tatiana Marques Jewelry may require physical inspection and supporting information before confirming any record.
29. ALTERATIONS AFTER CERTIFICATION
A Certificate of Authenticity describes the piece as documented when supplied or last formally recorded by Tatiana Marques Jewelry.
Subsequent alterations may change the specifications recorded on the original Certificate.
These may include:
resizing;
replacement of gemstones;
substantial refinishing;
metal alteration;
engraving;
structural modification;
or third party repair.
Where a material alteration is performed by Tatiana Marques Jewelry, the service history may be recorded and, where appropriate, updated documentation may be issued.
30. THIRD PARTY ALTERATIONS
Tatiana Marques Jewelry cannot certify the workmanship, materials or gemstones introduced into a piece by an unrelated third party.
If another jeweler materially alters a Tatiana Marques Jewelry piece, the original Certificate remains evidence of the piece as originally documented but may no longer accurately describe its current condition or specifications.
Tatiana Marques Jewelry may require inspection before providing any later authentication or updated record.
31. AUTHENTICATION OF TATIANA MARQUES JEWELRY PIECES
Where technically and administratively possible, Tatiana Marques Jewelry may assist with authentication of a piece believed to be an original Tatiana Marques Jewelry creation.
Authentication may require:
physical inspection;
comparison with atelier records;
photographs;
hallmarks;
construction details;
certificate references;
purchase history;
or other relevant evidence.
Possession of a document alone does not necessarily prove that a different physical piece is authentic.
Likewise, absence of an original Certificate does not automatically establish that a piece is not authentic.
32. VALUATION AND INSURANCE APPRAISALS
A Tatiana Marques Jewelry Certificate of Authenticity is not automatically an insurance valuation.
The original purchase price is also not necessarily the same as an appropriate future insurance replacement value.
Where an insurance company requires a formal valuation or appraisal, a separate document from an appropriately qualified professional may be necessary.
Tatiana Marques Jewelry may provide supporting specifications from its records where appropriate but does not represent every Certificate of Authenticity as an independent valuation.
33. RESALE VALUE
Neither an official hallmark, Tatiana Marques Jewelry Certificate of Authenticity nor independent gemstone report guarantees a future resale value.
Secondary market value may be influenced by many factors including:
market conditions;
condition;
rarity;
materials;
gemstones;
documentation;
provenance;
demand;
and the particular resale channel.
Certification should therefore be understood as documentation and verification within its stated scope, not as a promise of financial performance.
34. VINTAGE OR EXTERNAL JEWELRY
Where Tatiana Marques Jewelry accepts an older or third party piece for repair, transformation or reuse, existing marks may be recorded.
Recording an existing hallmark does not mean that Tatiana Marques Jewelry created the piece or independently confirms every aspect of its history.
Where an external article requires new legal assessment or marking because of the work performed, the relevant requirements will be considered according to the applicable precious metals regime.
35. HALLMARKS ON TRANSFORMED JEWELRY
A project involving transformation or reuse of existing jewelry may result in a new article that requires assessment and marking under the applicable precious metals rules.
The fact that the original source jewelry carried a hallmark does not necessarily mean that the newly created jewel can rely solely on that previous mark.
Where legally required, the final article will be submitted for the appropriate assay and marking process before being placed on the market.
36. INTERNATIONAL CLIENTS
Portuguese hallmarking applies according to the Portuguese legal regime relevant to Tatiana Marques Jewelry and the placing of precious metal articles on the market.
International destinations may have additional local requirements concerning precious metals, customs, gemstone documentation or importation.
Where jewelry is exported, applicable destination requirements may need to be considered separately.
Portuguese law also permits precious metal articles intended for countries participating in relevant international hallmarking arrangements to be marked according to the applicable international control framework where requested and appropriate.
37. HALLMARKS FROM OTHER COUNTRIES
Precious metal articles originating in another European Union or European Economic Area country may, under certain conditions, be recognised in Portugal without being re-assayed and marked by a Portuguese Assay Office.
The legal requirements include recognition and equivalence conditions designed to ensure that the foreign mark provides appropriate information and assurance concerning legal fineness.
Whether a particular foreign hallmark is sufficient must therefore be assessed under the applicable regime rather than assumed.
38. OFFICIAL HALLMARK INFORMATION
Portuguese precious metal traders are subject to consumer information obligations concerning official hallmark marks.
The Portuguese legal framework requires relevant operators to make the official Assay Office hallmark chart issued by the INCM immediately available to consumers, either in paper or electronic form.
Tatiana Marques Jewelry may therefore provide access to the current official hallmark chart through the website or another appropriate electronic method.
39. DAILY PRECIOUS METAL PRICES
Portuguese precious metal law also contains consumer information requirements concerning access to daily quotations for gold, silver, platinum and palladium through information linked to the Banco de Portugal.
Where legally applicable to Tatiana Marques Jewelry's commercial activity, this information will be made available through the appropriate website or client information mechanism.
40. CERTIFICATION DOES NOT REPLACE CARE
Hallmarking or certification does not make jewelry immune to wear, damage or the natural characteristics of its materials.
Precious metal fineness does not determine scratch resistance.
A certified gemstone may still be vulnerable to impact, abrasion, heat, chemicals or other conditions depending on the gemstone.
Clients should therefore follow the recommendations provided in the Jewelry Care & Maintenance page and any piece specific instructions supplied with their jewelry.
41. CERTIFICATION DOES NOT REPLACE THE LEGAL GUARANTEE
Official hallmarking, a Tatiana Marques Jewelry Certificate of Authenticity and independent gemstone documentation are separate from the statutory legal conformity guarantee.
The existence or absence of independent gemstone documentation does not remove the mandatory consumer rights applicable to the jewelry.
Full information concerning those rights is available in the Returns, Cancellations & Consumer Rights Policy.
42. DOCUMENTATION FOR BESPOKE PROJECTS
Depending on the project, a bespoke client may receive or generate several different documents during the commissioning process.
These may include:
Bespoke Design Agreement
Client Gold Intake and Custody Form, where applicable
Jewelry Proposal
Certificate of Authenticity
Independent Gemological Report, where applicable
Each document serves a distinct purpose.
A client should retain the final documentation supplied with the jewelry for future reference.
43. CONFIDENTIALITY AND PERSONAL INFORMATION
Certificates and gemstone reports may contain identifying references to a particular piece or project.
Tatiana Marques Jewelry manages client records in accordance with the Privacy Policy.
Where jewelry images or technical records can be retained without directly identifying a client, they may also form part of the atelier's creative and technical archive.
44. QUESTIONS ABOUT A HALLMARK OR CERTIFICATE
If a client is unsure about a hallmark, Certificate of Authenticity or gemstone document supplied with a Tatiana Marques Jewelry piece, the atelier may be contacted for clarification.
Where relevant, photographs or the physical piece may be required before technical information can be confirmed.
For questions concerning independent laboratory terminology, the issuing laboratory's own documentation should also be consulted.
45. RELATED POLICIES
This page should be read together with:
Terms & Conditions
Returns, Cancellations & Consumer Rights Policy
Jewelry Care & Maintenance
Privacy Policy
Contact Information
For bespoke projects involving client owned materials, the relevant Client Gold Intake and Custody Form and project documentation should also be consulted.
46. CONTACT
For questions concerning hallmarking, Certificates of Authenticity or gemstone documentation, please contact:
Tatiana Marques Jewelry
Operated by Fairies Ceremony Unipessoal Lda.
Email: geral@tatianamarquesjewelry.com
Telephone / WhatsApp: +351 966 690 768
Website: www.tatianamarquesjewelry.com