Modernist brooch

Siv Dahl · Jewelry · Demonstration Auction

Open auction lot

priority review

Acquisition position

Current all in cost

8275.0 SEK

Current bid or estimate6500.0 SEK

Modelled discount79.4%

Liquidity score88%

Potential market value

Specialist value interval

32760 to 45240 SEK

Value confidence88%

Comparable sales6

Evidence strength

83%

Identity confidence83%

Visual match80%

External references0

Market anomaly

93%

Information gap0%

Potential undervaluation79.4%

Risk profile

24%

Authenticity risk24%

Condition risk6%

Investigation rationale

Why this may be worth considering

strong visual recurrence or reference image match
marks, labels, signature or reference text supplied
provenance evidence supplied
maker or artist identity supplied
auction estimate is materially below the specialist model
all in acquisition cost is at least 55 percent below modelled value
all in acquisition cost is at least 75 percent below modelled value
Estimate materially below specialist value
Large gap to recent market history
Extreme price density anomaly
Important marks are not in the title
Weak catalogue discovery
very short catalogue title may reduce bidder discovery

Decision guardrails

What must be verified

no image

Visual laboratory

Add and compare research imagery

Object record

Known facts and missing information

ArtistSiv Dahl

MakerMissing

Mediumartist jewelry

Materials18k gold and sapphire

Dimensions5.0 × 7.0 × 1.0 cm

Weight28.0 g

Yearcirca 1960

EditionMissing

MarksSD Swedish assay marks

ConditionGood

ProvenanceOriginal fitted case

Modeljewelry_specialist 2.0.0

Modernist brooch. artist jewelry. 18k gold and sapphire. SD Swedish assay marks.

Identity resolution

Artist and maker hypotheses

Ranked from independent evidence. Confirmation or rejection becomes controlled training data.

0 candidates

Research pending

No identity hypotheses yet

Run global research after adding the clearest available front, back, marks and label images.

Closed deal feedback

Teach the valuation model

Enter the verified hammer price after the auction closes. Only verified outcomes become calibration data.

Learning guardrail

Truth before training

Unverified AI output is stored as a hypothesis only.
One-source matches are confidence capped.
Rejected matches improve source and feature calibration.
At least five verified closed sales are required per category.

Global research evidence

Reference material found elsewhere

0 references

Research pending

No external references stored

Run global research to search museum and authority collections.

Comparable logic

Specialist model explanation

6 category specific sold comparables selected
model uses jewelry specific identity, material, size and documentary fields
value interval uses weighted 20th, 50th and 80th percentiles with a dispersion adjustment
explicit category supplied

Comparable ID	Match	Price	Reasons
42	93%	50700.0 SEK	identity 100%, material 100%, size 92%, title 100%, hallmarks 100%, weight 93%
41	94%	45240.0 SEK	identity 100%, material 100%, size 94%, title 100%, hallmarks 100%, weight 95%
40	95%	40560.0 SEK	identity 100%, material 100%, size 99%, title 100%, hallmarks 100%, weight 98%
39	94%	36660.0 SEK	identity 100%, material 100%, size 100%, title 100%, hallmarks 100%, weight 99%
38	94%	32760.0 SEK	identity 100%, material 100%, size 98%, title 100%, hallmarks 100%, weight 96%
37	93%	28080.0 SEK	identity 100%, material 100%, size 93%, title 100%, hallmarks 100%, weight 93%

Automatic signature module

Every artwork image is checked for signatures and marks

The local engine detects and isolates candidate regions, searches the trusted mark library and runs conservative signature forensics. Optional AI interprets unreadable regions and creates research queries without changing the forensic verdict.

Candidate regions0

Signature regions0

AI enrichmentLocal only

PipelineNot run

No automatic mark result yet

The module runs during normal analysis when a local image is available.

Marks laboratory

Isolate and identify signatures, hallmarks and maker marks

110 independent methods generate cleanup variants, stroke and symbol descriptors, library matches, trust controls and conflict warnings.

Open mark library

Signature forensics

Check consistency with known genuine variation

This does not declare a signature genuine. It measures fit against a multi-source reference set, confusing signers and natural variation.

No forensic check yet

Run mark matching first, then compare the questioned signature against a sufficiently broad trusted reference set.