RAre Rolex ref 5100 " Texano"beta 21 mouvment
This is not a Datejust Oysterquartz. It is the Rolex Reference 5100, known to collectors as the "Texano", Rolex's first quartz wristwatch and one of the most radical watches in the brand's history. Introduced in 1970 and produced only until 1972, the 5100 preceded the in-house Oysterquartz collection by seven years. Its 18k yellow gold case, fluted bezel, and heavy integrated gold bracelet were created around the unusually large electronic movement within. The result is a boldly proportioned, unmistakably early 1970s Rolex whose design has no direct equivalent elsewhere in the catalogue.
The movement is the reason the 5100 matters. Rather than the later Rolex in-house Oysterquartz Calibres 5035 and 5055, this watch is powered by the CEH Beta 21, the landmark Swiss quartz calibre developed by the Centre Electronique Horloger consortium. Rolex participated in this joint Swiss response to the quartz revolution before developing its own quartz technology. The Beta 21 is not a conventional mass-market quartz movement: it uses an 8,192 Hz quartz oscillator, five stages of frequency division, and an electromechanical vibration motor operating at 256 Hz. Its architecture is markedly different from the 32 kHz stepper-motor movements of the later Oysterquartz line, and its substantial 7.5 mm height directly explains the Texano's strong 39 mm case and distinctive profile.
The 5100 was a technological statement at its launch. It was Rolex's first quartz watch, first model fitted with a sapphire crystal, and first to offer a quickset date. Each example was individually numbered, while the integrated bracelet and angular construction anticipated the design language that Rolex would later reinterpret in the Oysterquartz. The Texano nickname is generally associated with its oversized dimensions, exceptional weight, and unabashed 18k gold presence. It remains a rare and historically important reference for collectors who understand that this is not simply a quartz Rolex, but the first chapter in Rolex's electronic history.
Key Specifications
Reference
5100
Collector Name
"Texano"
Production Period
1970 to 1972
Case
18k yellow gold, approximately 39 mm, fluted bezel
Dial
Silver sunburst, applied gold baton indices, date at 3 o'clock
Bracelet
Integrated 18k yellow gold Rolex bracelet with faceted links
Movement
CEH Beta 21 quartz, Rolex designation RE10
Functions
Hours, minutes, central seconds, quickset date
Crystal
Sapphire crystal
Collector's Note
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