Jump to content

Reference:5100: Difference between revisions

From Rolexopedia
[checked revision][checked revision]
← Older edit
VisualWikitext
SEO fix: unlink nonexistent breadcrumb target (broken internal link)
Deep audit: correct Reference 5100 prose, hero placement, and gallery
 
(One intermediate revision by the same user not shown)
Line 10: Line 10:
<small>Beta 21 → '''5100'''</small>
<small>Beta 21 → '''5100'''</small>


Ref. 5100 is Rolex's first quartz wristwatch and its first watch fitted with a sapphire crystal. Rolex launched it on 5 June 1970, cased around the Beta 21, a 13-jewel, 8kHz quartz module developed jointly by the Centre Electronique Horloger (CEH), a consortium of roughly twenty Swiss watch houses that also included Omega, Patek Philippe, and Piaget. Each house cased the same shared movement under its own reference and its own design language; the case, dial and bracelet on the 5100 are Rolex's own work, the movement inside is not.
<div class="rp-lead">
[[File:Ref 5100 hero.webp|thumb|center|640px|alt=Rolex Beta 21 ref. 5100 in white gold, front view, on its integrated bracelet|Rolex Beta 21 ref. 5100 in 18K white gold, Phillips Hong Kong.]]
</div>


Rolex discontinued the 5100 in 1972 and left the CEH the same year, going on to spend five years developing its own in-house quartz calibers, the 5035 and 5055 that would power the Oysterquartz line from 1977. Auction catalogues also call the 5100 "Texano" or "The Texan," names that trace to dealer and auction-house usage rather than to Rolex.
Rolex launched Ref. 5100 on 5 June 1970 as its first quartz wristwatch. The watch used the 13-jewel, 8kHz Beta 21 module developed by the Centre Electronique Horloger (CEH), a consortium of about twenty Swiss watch houses that included Omega, Patek Philippe, and Piaget. Rolex designed the 5100's case, dial, and integrated bracelet around that shared movement; the movement itself was a consortium design.


[[File:Ref 5100 hero.webp|thumb|right|340px|alt=Rolex Beta 21 ref. 5100 in white gold, front view, on its integrated bracelet|Rolex Beta 21 ref. 5100 in 18K white gold, Phillips Hong Kong.]]
Rolex discontinued the 5100 in 1972 and left the CEH that year. It then developed the proprietary calibers 5035 and 5055 for the Oysterquartz line, introduced in 1977. Auction catalogues also call the 5100 "Texano" or "The Texan"; those names are used in dealer and auction-house catalogues rather than in the Rolex references cited here.


== Core facts ==
== Core facts ==
Line 29: Line 31:
|-
|-
| production
| production
| 1970–1972
| 1970-1972
|-
|-
| case materials
| case materials
Line 41: Line 43:
|-
|-
| crystal
| crystal
| sapphire — Rolex's first
| sapphire, Rolex's first
|-
|-
| movement
| movement
| Beta 21 quartz module, cal. RE10, Beta 21; 8kHz, 13 jewels (one lot records 15 — see Movement notes)
| Beta 21 quartz module, cal. RE10, Beta 21; 8kHz, 13 jewels (one lot records 15, see Movement notes)
|-
|-
| dial
| dial
Line 55: Line 57:
== Where it sits in the line ==
== Where it sits in the line ==


The 5100 answers the early-1970s quartz crisis from inside the industry that was under threat from it. Rather than developing a proprietary movement alone, Rolex joined the CEH alongside roughly twenty other Swiss manufacturers to pool the cost and risk of a workable quartz caliber. The Beta 21 that resulted powered watches across the consortium — Patek Philippe's ref. 3587 and IWC's Da Vinci among them — with each house free to design its own case and dial around the shared electronics.
The 5100 was Rolex's contribution to the CEH quartz project. Rolex joined about twenty other Swiss manufacturers instead of developing a movement alone. The resulting Beta 21 powered watches such as Patek Philippe ref. 3587 and the IWC Da Vinci, while each manufacturer designed its own case and dial.


Rolex's execution stands apart from the rest of its own catalogue at the time. Every other Rolex watch from 1970 used an Oyster case; the 5100 did not, because the Beta 21 would not fit inside one. The result is a non-Oyster, non-waterproof, screw-crowned tonneau case that reads as an outlier in Rolex's lineup rather than a natural extension of it — the movement dictated the case, not the reverse.
The 5100 differs from Rolex's other watches of the period. It uses a non-Oyster, non-waterproof tonneau case with a screw crown because the Beta 21's dimensions required a different case design. In this model, the movement set the case constraints.


The line that actually descends from the 5100 is not a family tree in the usual sense. After leaving the CEH in 1972, Rolex spent five years building its own quartz architecture from scratch, arriving at cal. 5035 and 5055 for the [[Reference:19018|Oysterquartz]] launched in 1977. The two movements share a "quartz" label and little else — the Beta 21 is a shared consortium design that Rolex could only modify in limited ways, while the Oysterquartz calibers are proprietary Rolex movements built to fit inside a conventional Oyster case. Treating the 5100 as an early Oysterquartz, as casual references to "Rolex's quartz history" sometimes do, collapses two different engineering stories into one.
After leaving the CEH in 1972, Rolex developed the proprietary calibers 5035 and 5055 for the [[Reference:19018|Oysterquartz]], launched in 1977. The Beta 21 was a shared consortium movement; the Oysterquartz calibers were Rolex designs made for a conventional Oyster case. The 5100 therefore belongs to the Beta 21 project rather than to the later Oysterquartz family.


== Production outline ==
== Production outline ==


Documented case numbers include 104, 184, 192 (twice), 644, 773, and 794, together with dealer references to numbers above 1,000. Individual watches carry an engraved limited-edition number rather than a conventional Rolex serial, and that numbering is the source of the reference's central unresolved question: nobody has published a confirmed total production figure.
Documented case numbers include 104, 184, 192 (twice), 644, 773, and 794, together with dealer references to numbers above 1,000. Individual watches carry an engraved edition number rather than a conventional Rolex serial. The published sources reviewed here do not establish a confirmed total production figure.


Christie's calls a 1,000-piece run — 900 in yellow gold, 100 in white gold — "believed" rather than confirmed. Hodinkee lays out three separate, mutually exclusive collector theories: something close to 700 yellow gold and 300 white gold; something closer to 900 and 100; or two separate batches of 900 yellow and 100 white apiece, for roughly 2,000 total. None of the three theories is sourced to a Rolex document, and the existence of numbers above 1,000 is used by more than one of them as supporting evidence, which is itself a sign that the "clean 1,000-piece run" framing understates what happened. The honest position is that production ran from 1970 to 1972, in two metals, in genuinely limited but not precisely known quantities.
Christie's calls a 1,000-piece run, 900 in yellow gold, 100 in white gold, "believed" rather than confirmed. Hodinkee lays out three separate, mutually exclusive collector theories: something close to 700 yellow gold and 300 white gold; something closer to 900 and 100; or two separate batches of 900 yellow and 100 white apiece, for roughly 2,000 total. None of the three theories is sourced to a Rolex production document, and the published examples include numbers above 1,000. The supported conclusion is narrower: production ran from 1970 to 1972 in yellow and white gold, while the total quantity remains undocumented in the sources reviewed here.


One case number turns up twice in the Phillips record. Case No. 192 sold at The Geneva Watch Auction: NINE in May 2019 for CHF62,500 against a CHF15,000–25,000 estimate, then reappeared at The Geneva Watch Auction: XX in 2024, selling for CHF48,260 against a CHF30,000–60,000 estimate. Two different watches carrying the identical case number at the same house, five years apart, is a coincidence nobody should reach for first — this is very likely one watch being re-consigned, not two.
One case number turns up twice in the Phillips record. Case No. 192 sold at The Geneva Watch Auction: NINE in May 2019 for CHF62,500 against a CHF15,000-25,000 estimate, then reappeared at The Geneva Watch Auction: XX in 2024, selling for CHF48,260 against a CHF30,000-60,000 estimate. The matching number and repeated auction description are consistent with one watch being re-consigned, but the records do not prove that.


== Movement notes ==
== Movement notes ==


The Beta 21 was not a Rolex design. The CEH developed it collaboratively, first showing a prototype in 1967. In 1968 the consortium's roughly twenty member houses agreed to produce about 6,000 of the movements, and a few hundred Beta 21 watches appeared at Baselworld in 1969 — a year before Rolex's own 5100 reached the market. One source puts the consortium at 21 watchmakers rather than 20; neither figure is resolved against the other here, and both are given with attribution rather than picking a winner. Rolex could make only limited modifications to the shared movement, which is the reason the case exists in the unusual form it does: the electronics came first, and the case had to be built around them.
The Beta 21 was not a Rolex design. The CEH developed it collaboratively, first showing a prototype in 1967. In 1968 the consortium's roughly twenty member houses agreed to produce about 6,000 of the movements, and a few hundred Beta 21 watches appeared at Baselworld in 1969, a year before Rolex's own 5100 reached the market. One source puts the consortium at 21 watchmakers rather than 20; neither figure is resolved against the other here, and both are given with attribution rather than picking a winner. Rolex could make only limited modifications to the shared movement, which is the reason the case exists in the unusual form it does: the electronics came first, and the case had to be built around them.


Rolex and the auction houses catalogue the movement as cal. RE10, Beta 21 — 8kHz, 13 jewels, in the descriptions given by Sotheby's, Christie's and Antiquorum. One Phillips lot (The Hong Kong Watch Auction: EIGHT) instead gives 15 jewels for the same designation. Nothing in the sourced record explains the gap, and no second lot corroborates it, so it reads as a catalogue transcription slip rather than a documented second variant.
Rolex and the auction houses catalogue the movement as cal. RE10, Beta 21, 8kHz, 13 jewels, in the descriptions given by Sotheby's, Christie's and Antiquorum. One Phillips lot (The Hong Kong Watch Auction: EIGHT) instead gives 15 jewels for the same designation. Nothing in the sourced record explains the gap, and no second lot corroborates it, so it reads as a catalogue transcription slip rather than a documented second variant.


What the 5100 does have, mechanically, that later quartz watches generally do not, is a true sweep centre-seconds hand, driven through a pallet wheel rather than the single-tick-per-second stepper motion common to quartz movements since. Christie's catalogue language singles this out as a design choice specific to the early Beta 21 generation, made obsolete once cheaper stepper-motor quartz became the industry standard.
The Beta 21 uses a sweep centre-seconds hand driven through a pallet wheel. Christie's describes this as a feature of the early Beta 21 generation; later quartz movements commonly used a stepper motor with a one-second jump.


Rolex's own successor movements, cal. 5035 and 5055, share none of this architecture. They are proprietary designs built five years later specifically to fit a standard Oyster case — a different engineering answer to a problem the Beta 21 had already tried to solve.
Rolex's own successor movements, cal. 5035 and 5055, share none of this architecture. They are proprietary designs built five years later specifically to fit a standard Oyster case, a different engineering answer to a problem the Beta 21 had already tried to solve.


== Dial map ==
== Dial map ==


Two documented dial colours track the two case metals: silvered dials on white gold cases, gilt or gold-coloured dials on yellow gold cases. Both carry "ROLEX" and "QUARTZ" printed on the dial, a date aperture at 3 o'clock, and — on at least one yellow gold example catalogued by Antiquorum — a Cyclops lens over the date. The dial text itself carries one detail worth noting for what it does not say: it reads "water resistant," not the "waterproof" language Rolex used across its Oyster-cased catalogue of the same years, a small wording difference that tracks the case's non-Oyster construction rather than a lesser build standard.
Two documented dial colours track the two case metals: silvered dials on white gold cases, gilt or gold-coloured dials on yellow gold cases. Both carry "ROLEX" and "QUARTZ" printed on the dial, a date aperture at 3 o'clock, and, on at least one yellow gold example catalogued by Antiquorum, a Cyclops lens over the date. The dial text itself carries one detail worth noting for what it does not say: it reads "water resistant," not the "waterproof" language Rolex used across its Oyster-cased catalogue of the same years, a small wording difference that tracks the case's non-Oyster construction rather than a lesser build standard.


== Case, bezel, crystal, and crown ==
== Case, bezel, crystal, and crown ==
Line 87: Line 89:
[[File:Ref 5100 caseback.webp|thumb|right|250px|alt=Caseback of a Rolex 5100 engraved with the limited-edition number 104|Caseback of case No. 104, engraved with its limited-edition number, Antiquorum Hong Kong.]]
[[File:Ref 5100 caseback.webp|thumb|right|250px|alt=Caseback of a Rolex 5100 engraved with the limited-edition number 104|Caseback of case No. 104, engraved with its limited-edition number, Antiquorum Hong Kong.]]


The case is tonneau-shaped and integrated with the bracelet, in a design Phillips catalogue copy calls "sharp angular architecture" — a genuine departure from the rounded Oyster case that defined every other Rolex watch of the period. Phillips lot text credits it as "the first time the Oyster case was redesigned," which is a slightly loose way of saying it: the 5100 does not use an Oyster case at all. It has a snap-on back rather than the screw-down Oyster back, and a fluted bezel that is one of the few visual threads connecting it to the rest of Rolex's catalogue.
The case is tonneau-shaped and integrated with the bracelet. Phillips describes its lines as angular and calls the design the first major departure from the Oyster case; the 5100 itself is not an Oyster case. It has a snap-on back and a fluted bezel.


Case diameter is given as approximately 39mm across the width on the majority of sourced lots — four separate Phillips lots and one Antiquorum lot agree on this figure. One Christie's lot gives 40mm, and Antiquorum records one example at 45 x 39mm, measuring both axes of the tonneau shape rather than a single diameter. Taken together, these read as measurement-convention differences on a non-round case rather than evidence of more than one case size.
Case diameter is given as approximately 39mm across the width on the majority of sourced lots, four separate Phillips lots and one Antiquorum lot agree on this figure. One Christie's lot gives 40mm, and Antiquorum records one example at 45 x 39mm, measuring both axes of the tonneau shape rather than a single diameter. Taken together, these read as measurement-convention differences on a non-round case rather than evidence of more than one case size.


Every documented case is 18K gold, yellow or white, with no steel examples surfacing across the sourced auction record. White gold examples are consistently described as the scarcer of the two: Phillips catalogue language calls white gold "exceedingly rarer" and states that "no more than a handful" of white gold examples have ever come to auction, while Christie's puts a number on it directly — fewer than 15 differently numbered white gold examples sold at auction in the twenty years before its 2022 lot.
Every documented case is 18K gold, yellow or white, with no steel examples surfacing across the sourced auction record. White gold examples are consistently described as the scarcer of the two: Phillips catalogue language calls white gold "exceedingly rarer" and states that "no more than a handful" of white gold examples have ever come to auction, while Christie's puts a number on it directly, fewer than 15 differently numbered white gold examples sold at auction in the twenty years before its 2022 lot.


The crystal is synthetic sapphire, a first for Rolex across its whole catalogue, not only within the 5100's own line. It would be years before sapphire crystal became standard across the rest of Rolex's production.
The crystal is synthetic sapphire. Rolex and auction catalogues describe the 5100 as the brand's first watch to use sapphire; sapphire became more common in later Rolex production.


== Bracelets, end links, and clasps ==
== Bracelets, end links, and clasps ==
Line 103: Line 105:
== Special branches: the CEH consortium and the Beta 21 ==
== Special branches: the CEH consortium and the Beta 21 ==


The 5100 cannot be told apart from the movement it shares with roughly twenty other Swiss watch houses, so a short account of that consortium belongs here. The Centre Electronique Horloger began work toward a viable quartz wristwatch caliber in the early 1960s, aiming to answer the same question the whole Swiss industry would eventually be forced to answer by Japanese quartz competition: whether a mechanical-watch country could build electronics good enough to matter. A first-generation module, Beta 1, arrived in 1960; the Beta 21 that followed in 1969 was the version that reached series production, rated to 5 seconds a month — accurate enough to outperform any mechanical watch on the market at the time it launched.
The 5100 uses the Beta 21 movement shared by the CEH consortium. The Centre Electronique Horloger began work on a quartz wristwatch caliber in the early 1960s. Sources cited for the project describe a Beta 1 prototype in 1960 and the Beta 21 entering series production in 1969, with a stated accuracy of about five seconds per month.


Every CEH member cased the identical movement under its own reference and its own design language. Patek Philippe's ref. 3587 and the IWC Da Vinci both ran on the same Beta 21 that powers the 5100; only the case, dial, and finishing separate them, since the electronics inside are not brand-specific at all. Rolex's own contribution to that design language was the angular tonneau case described above — a shape unlike anything else the brand made before or after it.
CEH members used the shared Beta 21 under their own references and case designs. Patek Philippe ref. 3587 and the IWC Da Vinci are documented examples. Rolex's contribution was the angular tonneau case used for the 5100.


The consortium did not last. By 1972, Rolex had discontinued the 5100 and left the CEH outright, unwilling to keep sharing an identical movement with more than a dozen competing manufacturers. What followed was five years of independent development, ending in the Oysterquartz calibers 5035 and 5055 — proprietary Rolex electronics built specifically to fit inside a standard Oyster case, the opposite design constraint from the one that produced the 5100.
By 1972, Rolex had discontinued the 5100 and left the CEH. It then spent five years developing the proprietary Oysterquartz calibers 5035 and 5055, designed to fit a standard Oyster case.


== Auction record ==
== Auction record ==
Line 122: Line 124:
| white gold, new-old-stock
| white gold, new-old-stock
| 794
| 794
| estimate CHF100,000–150,000
| estimate CHF100,000-150,000
|-
|-
| Christie's, Geneva
| Christie's, Geneva
| May 2017
| May 2017
| yellow gold
| yellow gold
| —
| n/a
| estimate CHF15,000–25,000
| estimate CHF15,000-25,000
|-
|-
| Sotheby's
| Sotheby's
| 2014
| 2014
| white gold, full set
| white gold, full set
| —
| n/a
| sold CHF125,000 (estimate CHF30,000–50,000)
| sold CHF125,000 (estimate CHF30,000-50,000)
|-
|-
| Sotheby's
| Sotheby's
| 2013
| 2013
| white gold
| white gold
| —
| n/a
| sold CHF32,500 (estimate CHF15,000–25,000)
| sold CHF32,500 (estimate CHF15,000-25,000)
|-
|-
| Phillips, The Geneva Watch Auction: NINE
| Phillips, The Geneva Watch Auction: NINE
Line 146: Line 148:
| white gold
| white gold
| 192
| 192
| sold CHF62,500 (estimate CHF15,000–25,000)
| sold CHF62,500 (estimate CHF15,000-25,000)
|-
|-
| Phillips, The Geneva Watch Auction: XX
| Phillips, The Geneva Watch Auction: XX
Line 152: Line 154:
| white gold
| white gold
| 192
| 192
| sold CHF48,260 (estimate CHF30,000–60,000)
| sold CHF48,260 (estimate CHF30,000-60,000)
|-
|-
| Phillips, The Hong Kong Watch Auction: FIVE
| Phillips, The Hong Kong Watch Auction: FIVE
| —
| n/a
| white gold
| white gold
| 184
| 184
| estimate HK$350,000–550,000
| estimate HK$350,000-550,000
|-
|-
| Phillips, The Hong Kong Watch Auction: EIGHT
| Phillips, The Hong Kong Watch Auction: EIGHT
| —
| n/a
| yellow gold ("Texano")
| yellow gold ("Texano")
| 644
| 644
| estimate HK$160,000–250,000
| estimate HK$160,000-250,000
|-
|-
| Sotheby's, Important Watches: Part II
| Sotheby's, Important Watches: Part II
| —
| n/a
| white gold ("The Texan")
| white gold ("The Texan")
| 225/87
| 225/87
| estimate CHF30,000–50,000
| estimate CHF30,000-50,000
|-
|-
| Sotheby's, Watches Weekly, Geneva
| Sotheby's, Watches Weekly, Geneva
| —
| n/a
| yellow gold ("The Texan")
| yellow gold ("The Texan")
| 315/249
| 315/249
| estimate CHF12,000–18,000
| estimate CHF12,000-18,000
|-
|-
| Antiquorum, Hong Kong
| Antiquorum, Hong Kong
Line 182: Line 184:
| yellow gold
| yellow gold
| 104
| 104
| estimate HKD135,000–230,000
| estimate HKD135,000-230,000
|-
|-
| Christie's, New York, Kairos Collection Part III
| Christie's, New York, Kairos Collection Part III
Line 191: Line 193:
|}
|}


The 192/192 repeat aside, this is not a large enough or currency-consistent enough sample to support a pricing trend. Results range across three currencies and a decade, mix full-set and watch-only lots, and skew toward white gold simply because that is the metal collectors and auction houses have written the most about. What the record does establish cleanly is that four separate major auction houses — Christie's, Phillips, Sotheby's and Antiquorum — have each catalogued the 5100 under its own reference number, independently of one another.
The auction sample is too small and spans several currencies and years to support a price trend. It also mixes full sets with watch-only lots and contains more white-gold records than yellow-gold records. Christie's, Phillips, Sotheby's, and Antiquorum each catalogue the 5100 in the records listed here.
 
<gallery mode="packed" heights="180">
File:Ref 5100 hero.webp|Rolex 5100 Beta 21, front view
File:Ref 5100 caseback.webp|Caseback with engraved edition number
File:Ref 5100 bracelet.webp|Integrated gold bracelet
</gallery>


== Sources ==
== Sources ==


* [https://www.christies.com/en/lot/lot-6378255 "Christie's, Important Watches of Exceptional Provenance Featuring The Kairos Collection Part III, New York, 2022, Lot 104", Christie's]
* src-christies-2022-5100-wg-773
* [https://phillips.com/detail/rolex/111786 "Phillips, The Hong Kong Watch Auction: FIVE, Lot 902", Phillips]
* src-phillips-hk5-5100-wg-902
* [https://www.phillips.com/detail/rolex/205916 "Phillips, The Geneva Watch Auction: XX, Lot 182", Phillips]
* src-phillips-genevaxx-5100-wg-182
* [https://phillips.com/detail/rolex/126470 "Phillips, The Geneva Watch Auction: NINE, Lot 10", Phillips]
* src-phillips-genevaix-5100-wg-126470
* [https://www.phillips.com/detail/rolex/126954 "Phillips, The Hong Kong Watch Auction: EIGHT, Lot 1116", Phillips]
* src-phillips-hk8-5100-yg-texano-1116
* [https://www.sothebys.com/buy/dbce6987-dc44-4308-a36a-179fcc8226db/lots/65c29dac-201f-4061-a0bc-2c546d128a50 "Sotheby's, Important Watches: Part II, Lot 427", Sotheby's]
* src-sothebys-5100-wg-importantwatchespart2
* [https://www.sothebys.com/buy/4d07464b-af10-492f-a1e7-e96532e27de5/lots/3a360627-6a4b-4c7e-9734-a2be28cecfa1 "Sotheby's, Watches Weekly, Geneva, Lot 7", Sotheby's]
* src-sothebys-5100-yg-watchesweekly
* [https://catalog.antiquorum.swiss/en/lots/rolex-ref-5100-quartz-lot-330-325 "Antiquorum, Important Modern & Vintage Timepieces, Hong Kong, 23 July 2020, Lot 325", Antiquorum]
* src-antiquorum-2020-5100-yg-lot325
* [https://www.hodinkee.com/articles/rolexs-first-quartz-watch-5100-christies-geneva Cara Barrett, "Found: Rolex's Very First Quartz Watch For Sale At Christie's", Hodinkee, 2017-05-12]
* src-hodinkee-2017-barrett-5100-christies
* [http://www.oysterquartz.net/the_quartz_date_5100.htm "The Quartz Date 5100", Oysterquartz.net]
* src-oysterquartz-net-5100-quartzdate
* [https://www.the1916company.com/blog/rolex-quartz-movement.html The 1916 Company editorial, "Rolex Quartz Movement History: Beta 21, Oysterquartz & Rare Models", The 1916 Company]
* [https://www.the1916company.com/blog/rolex-quartz-movement.html The 1916 Company editorial, "Rolex Quartz Movement History: Beta 21, Oysterquartz & Rare Models", The 1916 Company]


[[Category:Beta-21]]
[[Category:Beta-21]]
--- 12460 chars, 0 images ---

Latest revision as of 09:46, 29 September 2026


Beta 21 → 5100

Rolex Beta 21 ref. 5100 in white gold, front view, on its integrated bracelet
Rolex Beta 21 ref. 5100 in 18K white gold, Phillips Hong Kong.

Rolex launched Ref. 5100 on 5 June 1970 as its first quartz wristwatch. The watch used the 13-jewel, 8kHz Beta 21 module developed by the Centre Electronique Horloger (CEH), a consortium of about twenty Swiss watch houses that included Omega, Patek Philippe, and Piaget. Rolex designed the 5100's case, dial, and integrated bracelet around that shared movement; the movement itself was a consortium design.

Rolex discontinued the 5100 in 1972 and left the CEH that year. It then developed the proprietary calibers 5035 and 5055 for the Oysterquartz line, introduced in 1977. Auction catalogues also call the 5100 "Texano" or "The Texan"; those names are used in dealer and auction-house catalogues rather than in the Rolex references cited here.

Core facts

detail value
reference 5100
model names Beta 21; also catalogued as "Texano" or "The Texan"
production 1970-1972
case materials 18K yellow gold, 18K white gold
case diameter approximately 39mm across the width (tonneau case; see Case, bezel, crystal, and crown)
case shape tonneau, angular
crystal sapphire, Rolex's first
movement Beta 21 quartz module, cal. RE10, Beta 21; 8kHz, 13 jewels (one lot records 15, see Movement notes)
dial silvered (white gold cases) or gilt/gold-coloured (yellow gold cases); text reads "water resistant," not "waterproof"
bracelet integrated, same metal as the case, concealed deployant clasp

Where it sits in the line

The 5100 was Rolex's contribution to the CEH quartz project. Rolex joined about twenty other Swiss manufacturers instead of developing a movement alone. The resulting Beta 21 powered watches such as Patek Philippe ref. 3587 and the IWC Da Vinci, while each manufacturer designed its own case and dial.

The 5100 differs from Rolex's other watches of the period. It uses a non-Oyster, non-waterproof tonneau case with a screw crown because the Beta 21's dimensions required a different case design. In this model, the movement set the case constraints.

After leaving the CEH in 1972, Rolex developed the proprietary calibers 5035 and 5055 for the Oysterquartz, launched in 1977. The Beta 21 was a shared consortium movement; the Oysterquartz calibers were Rolex designs made for a conventional Oyster case. The 5100 therefore belongs to the Beta 21 project rather than to the later Oysterquartz family.

Production outline

Documented case numbers include 104, 184, 192 (twice), 644, 773, and 794, together with dealer references to numbers above 1,000. Individual watches carry an engraved edition number rather than a conventional Rolex serial. The published sources reviewed here do not establish a confirmed total production figure.

Christie's calls a 1,000-piece run, 900 in yellow gold, 100 in white gold, "believed" rather than confirmed. Hodinkee lays out three separate, mutually exclusive collector theories: something close to 700 yellow gold and 300 white gold; something closer to 900 and 100; or two separate batches of 900 yellow and 100 white apiece, for roughly 2,000 total. None of the three theories is sourced to a Rolex production document, and the published examples include numbers above 1,000. The supported conclusion is narrower: production ran from 1970 to 1972 in yellow and white gold, while the total quantity remains undocumented in the sources reviewed here.

One case number turns up twice in the Phillips record. Case No. 192 sold at The Geneva Watch Auction: NINE in May 2019 for CHF62,500 against a CHF15,000-25,000 estimate, then reappeared at The Geneva Watch Auction: XX in 2024, selling for CHF48,260 against a CHF30,000-60,000 estimate. The matching number and repeated auction description are consistent with one watch being re-consigned, but the records do not prove that.

Movement notes

The Beta 21 was not a Rolex design. The CEH developed it collaboratively, first showing a prototype in 1967. In 1968 the consortium's roughly twenty member houses agreed to produce about 6,000 of the movements, and a few hundred Beta 21 watches appeared at Baselworld in 1969, a year before Rolex's own 5100 reached the market. One source puts the consortium at 21 watchmakers rather than 20; neither figure is resolved against the other here, and both are given with attribution rather than picking a winner. Rolex could make only limited modifications to the shared movement, which is the reason the case exists in the unusual form it does: the electronics came first, and the case had to be built around them.

Rolex and the auction houses catalogue the movement as cal. RE10, Beta 21, 8kHz, 13 jewels, in the descriptions given by Sotheby's, Christie's and Antiquorum. One Phillips lot (The Hong Kong Watch Auction: EIGHT) instead gives 15 jewels for the same designation. Nothing in the sourced record explains the gap, and no second lot corroborates it, so it reads as a catalogue transcription slip rather than a documented second variant.

The Beta 21 uses a sweep centre-seconds hand driven through a pallet wheel. Christie's describes this as a feature of the early Beta 21 generation; later quartz movements commonly used a stepper motor with a one-second jump.

Rolex's own successor movements, cal. 5035 and 5055, share none of this architecture. They are proprietary designs built five years later specifically to fit a standard Oyster case, a different engineering answer to a problem the Beta 21 had already tried to solve.

Dial map

Two documented dial colours track the two case metals: silvered dials on white gold cases, gilt or gold-coloured dials on yellow gold cases. Both carry "ROLEX" and "QUARTZ" printed on the dial, a date aperture at 3 o'clock, and, on at least one yellow gold example catalogued by Antiquorum, a Cyclops lens over the date. The dial text itself carries one detail worth noting for what it does not say: it reads "water resistant," not the "waterproof" language Rolex used across its Oyster-cased catalogue of the same years, a small wording difference that tracks the case's non-Oyster construction rather than a lesser build standard.

Case, bezel, crystal, and crown

Caseback of a Rolex 5100 engraved with the limited-edition number 104
Caseback of case No. 104, engraved with its limited-edition number, Antiquorum Hong Kong.

The case is tonneau-shaped and integrated with the bracelet. Phillips describes its lines as angular and calls the design the first major departure from the Oyster case; the 5100 itself is not an Oyster case. It has a snap-on back and a fluted bezel.

Case diameter is given as approximately 39mm across the width on the majority of sourced lots, four separate Phillips lots and one Antiquorum lot agree on this figure. One Christie's lot gives 40mm, and Antiquorum records one example at 45 x 39mm, measuring both axes of the tonneau shape rather than a single diameter. Taken together, these read as measurement-convention differences on a non-round case rather than evidence of more than one case size.

Every documented case is 18K gold, yellow or white, with no steel examples surfacing across the sourced auction record. White gold examples are consistently described as the scarcer of the two: Phillips catalogue language calls white gold "exceedingly rarer" and states that "no more than a handful" of white gold examples have ever come to auction, while Christie's puts a number on it directly, fewer than 15 differently numbered white gold examples sold at auction in the twenty years before its 2022 lot.

The crystal is synthetic sapphire. Rolex and auction catalogues describe the 5100 as the brand's first watch to use sapphire; sapphire became more common in later Rolex production.

Bracelets, end links, and clasps

Angled view of a white gold Rolex 5100 showing the faceted integrated bracelet
Integrated faceted-link bracelet on a white gold example, Phillips Hong Kong.

The bracelet is integrated with the case rather than a separate fitment, built in the same 18K gold as the case, with a concealed deployant clasp. One Antiquorum-catalogued yellow gold example names its bracelet maker directly: Jean-Pierre Ecoffey of Geneva, a detail not repeated on any of the other sourced lots and not established here as the standard supplier for the line as a whole. Bracelet lengths recorded across the sourced lots run from about 170mm to 200mm, consistent with an adjustable integrated design rather than a fixed single length.

Special branches: the CEH consortium and the Beta 21

The 5100 uses the Beta 21 movement shared by the CEH consortium. The Centre Electronique Horloger began work on a quartz wristwatch caliber in the early 1960s. Sources cited for the project describe a Beta 1 prototype in 1960 and the Beta 21 entering series production in 1969, with a stated accuracy of about five seconds per month.

CEH members used the shared Beta 21 under their own references and case designs. Patek Philippe ref. 3587 and the IWC Da Vinci are documented examples. Rolex's contribution was the angular tonneau case used for the 5100.

By 1972, Rolex had discontinued the 5100 and left the CEH. It then spent five years developing the proprietary Oysterquartz calibers 5035 and 5055, designed to fit a standard Oyster case.

Auction record

Sale Date Metal Case No. Result
Christie's, Geneva May 2017 white gold, new-old-stock 794 estimate CHF100,000-150,000
Christie's, Geneva May 2017 yellow gold n/a estimate CHF15,000-25,000
Sotheby's 2014 white gold, full set n/a sold CHF125,000 (estimate CHF30,000-50,000)
Sotheby's 2013 white gold n/a sold CHF32,500 (estimate CHF15,000-25,000)
Phillips, The Geneva Watch Auction: NINE 12 May 2019 white gold 192 sold CHF62,500 (estimate CHF15,000-25,000)
Phillips, The Geneva Watch Auction: XX 2024 white gold 192 sold CHF48,260 (estimate CHF30,000-60,000)
Phillips, The Hong Kong Watch Auction: FIVE n/a white gold 184 estimate HK$350,000-550,000
Phillips, The Hong Kong Watch Auction: EIGHT n/a yellow gold ("Texano") 644 estimate HK$160,000-250,000
Sotheby's, Important Watches: Part II n/a white gold ("The Texan") 225/87 estimate CHF30,000-50,000
Sotheby's, Watches Weekly, Geneva n/a yellow gold ("The Texan") 315/249 estimate CHF12,000-18,000
Antiquorum, Hong Kong 23 July 2020 yellow gold 104 estimate HKD135,000-230,000
Christie's, New York, Kairos Collection Part III 2022 white gold 773 lot 104

The auction sample is too small and spans several currencies and years to support a price trend. It also mixes full sets with watch-only lots and contains more white-gold records than yellow-gold records. Christie's, Phillips, Sotheby's, and Antiquorum each catalogue the 5100 in the records listed here.

  • Rolex 5100 Beta 21, front view
    Rolex 5100 Beta 21, front view
  • Caseback with engraved edition number
    Caseback with engraved edition number
  • Integrated gold bracelet
    Integrated gold bracelet

Sources


--- 12460 chars, 0 images ---

Retrieved from "https://rolexopedia.net/index.php?title=Reference:5100&oldid=11396"