How much will a dealer pay for a Must de Cartier 21?

Dealers buying to resell usually bid about 75 to 85% of public market value, because they carry the cost and risk of the resale. For a 31 mm steel or steel and gold quartz Must de Cartier 21 at the recent median of $950, that suggests bids of roughly $700 to $800. Archiva is opening a panel of specialist dealers who bid blind, with the seller keeping the whole winning bid.

What is the Must de Cartier 21?

A round quartz watch from Cartier's Must line with a wide bezel and a cabochon crown, made in stainless steel or steel with gold-colored elements and in several sizes. Auction houses catalog it as the Must de Cartier 21 or the Must 21.

When was the Must 21 introduced?

La Souveraine's catalog says the 21 was introduced in 1989, its name heralding the 21st century, and Battin Enchères dates an early example to circa 1990. Antiquorum dated one steel and gold example, case 901038068, to circa 1980, earlier than any other source allows; we treat that date as a loose estimate.

Which Must 21 reference do I have?

Read the case back and measure the case. Early watches carry a nine-digit case number beginning 9010 or 9011, and catalogs describe them from 30 to 35 mm, so those digits do not identify a size. Later watches print a four-digit reference: the [Ref. 1330](/cartier/must-21/ref-1330) is the 31 mm size and the [Ref. 1340](/cartier/must-21/ref-1340) the mid-size, about 28 mm.

Is the Must 21 gold or gold-plated?

The case is stainless steel. On two-tone examples the catalogs we consulted describe the gold element in different words: Battin Enchères calls it gilt metal, La Souveraine gold-plated metal, and Antiquorum, Bonhams and Bukowskis simply gold. Check the case back stamps and the edges of the bezel and links for wear through the finish.

What should I check before buying a Must 21?

The case back number and the size; the bezel, crown and links for wear through any gold finish; the bracelet for stretched links and the clasp for a firm close; the case side for dents; and a quartz movement that runs. Papers dating the watch help, since few Must 21 lots carry a firm date.

Cartier

Must de Cartier 21

The round steel Must watch with a wide bezel, introduced in 1989 according to La Souveraine's catalog: quartz, in steel or steel with gold, and made in several sizes.

What's it worth?View references Collector's Corner

History

Origins

The Must de Cartier 21 is the round steel watch of Cartier's Must line. La Souveraine's catalog says it was introduced in 1989, its name heralding the 21st century. Battin Enchères dates an early example to circa 1990. Antiquorum dated a steel and gold example, case 901038068, to circa 1980, which no other source supports; we treat it as a loose estimate.

The Early Must 21

Battin Enchères describes an early 31 mm example in steel and gilt metal with a wide bezel engraved with Roman numerals and a railway minute track, and a crown set with a cabochon. Their case numbers run to nine digits and begin 9010 or 9011: Antiquorum has sold examples numbered 901038068 and 901101982, Fellows one numbered 901029134, and La Souveraine one numbered 901188527. These early numbers cover more than one size. Catalogs describe 9010 and 9011 cases at 30 to 31 mm, Fellows a 35 mm example numbered 901155103 on the Cal. 87.06, and La Souveraine a larger case it measures at 38 × 36 mm with a date at 6 o'clock. Archiva does not yet treat either number as a reference with its own page.

The Later References

Later Must 21 watches print a four-digit reference with a serial that begins with two letters. Fellows and Bonhams catalog the Ref. 1330 at 31 mm, in stainless steel or steel and gold, on the quartz Cal. 690 or Cal. 90.06; no catalog dates one before Bonhams' example purchased in September 2009, and the retailer Chrono.dk listed one sold new by a Danish authorized dealer in April 2001. The mid-size Ref. 1340, about 28 mm, appears at Fellows and Bukowskis; Fellows sold one with a Cartier guarantee booklet dated November 1998. Fellows describes both with a chapter ring bezel and a silvered dial.

The Must 21 Today

The Must 21 changes hands often at regional and online sales, usually on its signed steel or bi-color bracelet. Few lots carry a firm date, so Cartier papers matter more than usual in placing a watch within the line.

Quintessential Reference

Ref. 1340 · c. 1998

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Reference: 1340; Mid-size, stainless steel or steel and gold, quartz
Year: c. 1998; Fellows sold one with a guarantee booklet dated November 1998; no source we opened gives a first or last year of production
Movement: Quartz; Signed Cartier quartz; Fellows catalogs the Cal. 690 on two examples and the Cal. 90 and Cal. 90.06 on two others
Case: 28 mm, Stainless Steel
Dial: Silvered; Silvered dial inside a chapter ring bezel
Hands: Not described in the catalogs consulted; Not described in the catalogs consulted
Crystal: Sapphire; Bukowskis lists a sapphire crystal
Strap: Steel or bi-color bracelet; Signed bracelet with a double folding clasp, in stainless steel or steel and gold

The Ref. 1340 is the mid-size Must 21: a stainless steel case of about 28 mm with a chapter ring bezel, a silvered dial and a signed Cartier quartz movement, on a steel or bi-color bracelet with a double folding clasp. Fellows has sold one with a Cartier guarantee booklet dated November 1998, and Bukowskis one with its box and certificate.

Other Known References

2 documented references across 1 era

Modern Manufacture1993–2001

2 refs

	Reference	Case Material	Movement	Case Size	Dial	Crystal
	Ref. 1330Stainless Steel · Quartz	Stainless Steel	Quartz	31 mm	Silvered	Not described in the catalogs consulted
	Ref. 1340Stainless Steel · Quartz	Stainless Steel	Quartz	28 mm	Silvered	Sapphire

What is a Must de Cartier 21 worth?

Choose your reference, set its condition, and see what it's likely to bring. Each estimate uses sales of that exact reference where there are enough of them.

Which reference is yours?Ref. 133031 mm, stainless steel or steel and gold, quartz1 saleRef. 1340Mid-size, stainless steel or steel and gold, quartzStill gathering

ConditionVery good

Needs workFairVery goodExcellentExceptional

The typical public example: light wear, original-looking dial, runs well. This is the baseline.

Original box and papers+8% on the estimateRecent Cartier service, with papers+5% on the estimateOriginal Cartier bracelet, all links present+5% on the estimateDial replaced or refinished−10% on the estimate

Estimated market value

One sale of Ref. 1330: $1,050 at Bonhams London, Sep 2025. Too few to estimate from.

For comparison

31 mm, steel or steel and gold, quartz (Ref. 1330 and 9011): two sales, $900 and $1,050, one of them Ref. 1330.

What a dealer would likely payNot enough sales

See the sale of Ref. 1330 and the 1 sale it is compared with

Date	Ref.	Where	Details	Counts as	Price
Sep 2025	1330	Bonhams LondonAuction	Knightsbridge online, lot 24, 22 Aug to 3 Sep 2025. Steel and gold, 31 mm, Cal. 690, purchased 2009, box and papers. Sold for, including premium.	This reference	£768≈ $1,050
Mar 2026	9011	Antiquorum Hong KongAuction	Lot 21, 13 Mar 2026. Steel and gold, 31 mm, case 901101982, Cal. 81.	Comparable	HK$6,930≈ $900

Sales from November 2023 to November 2026, or from the last five years for a reference with fewer than three in that time. Only sales that name a reference count toward its estimate; sales of the rest of its version are shown for comparison and never folded in. Auction prices include the buyer's premium unless a row says hammer; dealer prices are the price at sale. Pound and Hong Kong dollar figures are converted at a rate near each sale date. Results are from the auction houses' own lot pages. Bonhams includes the buyer's premium; Antiquorum shows a sold figure without stating it. Fellows shows results only to signed-in users, so its sales are not included. The condition and option adjustments, the expected bid (75 to 85% of market value) and the auction range (62 to 72%) are working assumptions, to be replaced by Archiva's own bids as they come in. A sale far above or below the other sales of its reference is listed but not counted, so one unusual result can't pull the estimate. An estimate from public results, not an appraisal.

Collector's Corner

What every buyer, inheritor, and first-time collector should know.

Buying Guide

01DIAL

The Secret Signature

Introduced 1977

A microscopic 'CARTIER' hidden within the Roman numerals, present on every genuine post-1977 dial.

02CASE

Case Back Hallmarks

Varies by origin and era

A Cartier case carries the Cartier signature, a reference and serial number on later pieces, and small struck marks for the metal and the case maker. Which marks appear depends on where the case was made: an eagle's head on Paris gold, JC and a date letter on London cases, the Helvetia head on Swiss 18k before 1995. The hallmarks guide shows what each one means.

03MOVEMENT

Movement Sourcing

Varies by era and model

Cartier sourced movements from various Swiss manufacturers throughout history, including Jaeger-LeCoultre, Frédéric Piguet, ETA, and in-house production. Knowing the correct caliber for a specific reference is essential for identifying the watch and establishing provenance.

04CROWN

Crown Sapphire Cabochon

A Cartier hallmark since the early 20th century

The blue sapphire (or spinel on less precious models) cabochon crown is a Cartier signature. Original crowns show consistent color saturation and are set flush with the crown body. Replacements often show misalignment or incorrect stone dimensions that reveal themselves under magnification.

05BRACELET

Bracelet and Clasp Markings

Check the clasp first

Cartier bracelets carry their own reference markings and the deployment clasp should bear the Cartier name and logo. Aftermarket bracelets are extremely common on vintage pieces, so checking that the clasp is original and that reference numbers match is crucial to the overall picture.

06DIAL

Dial Aging and Patina

Patina tells the story

Vintage Cartier dials develop characteristic aging: cream dials warm to ivory, lacquer dials may develop fine crazing, and applied indices can show legible wear patterns. Understanding acceptable versus concerning dial aging is key to valuing a vintage piece accurately.

Questions collectors ask

Direct answers about the Must de Cartier 21, drawn from the reference records below.

What is a Must de Cartier 21 worth?: Public auction and dealer results from November 2023 to November 2026 put the 31 mm steel or steel and gold quartz (Ref. 1330, 9011) at $900 to $1,000, median $950 across 2 sales. Condition, a recent Cartier service, and the original box and papers move an individual watch within or beyond these ranges, and the calculator on this page adjusts for each.
How much will a dealer pay for a Must de Cartier 21?: Dealers buying to resell usually bid about 75 to 85% of public market value, because they carry the cost and risk of the resale. For a 31 mm steel or steel and gold quartz Must de Cartier 21 at the recent median of $950, that suggests bids of roughly $700 to $800. Archiva is opening a panel of specialist dealers who bid blind, with the seller keeping the whole winning bid.
What is the Must de Cartier 21?: A round quartz watch from Cartier's Must line with a wide bezel and a cabochon crown, made in stainless steel or steel with gold-colored elements and in several sizes. Auction houses catalog it as the Must de Cartier 21 or the Must 21.
When was the Must 21 introduced?: La Souveraine's catalog says the 21 was introduced in 1989, its name heralding the 21st century, and Battin Enchères dates an early example to circa 1990. Antiquorum dated one steel and gold example, case 901038068, to circa 1980, earlier than any other source allows; we treat that date as a loose estimate.
Which Must 21 reference do I have?: Read the case back and measure the case. Early watches carry a nine-digit case number beginning 9010 or 9011, and catalogs describe them from 30 to 35 mm, so those digits do not identify a size. Later watches print a four-digit reference: the [Ref. 1330](/cartier/must-21/ref-1330) is the 31 mm size and the [Ref. 1340](/cartier/must-21/ref-1340) the mid-size, about 28 mm.
Is the Must 21 gold or gold-plated?: The case is stainless steel. On two-tone examples the catalogs we consulted describe the gold element in different words: Battin Enchères calls it gilt metal, La Souveraine gold-plated metal, and Antiquorum, Bonhams and Bukowskis simply gold. Check the case back stamps and the edges of the bezel and links for wear through the finish.
What should I check before buying a Must 21?: The case back number and the size; the bezel, crown and links for wear through any gold finish; the bracelet for stretched links and the clasp for a firm close; the case side for dents; and a quartz movement that runs. Papers dating the watch help, since few Must 21 lots carry a firm date.

Next Steps

INHERITOR