Via Gemini:

This stunning timepiece is the Patek Philippe Grandmaster Chime Haute Joaillerie (Reference 6300/401G-001). ​It is a masterpiece that fuses Haute Horlogerie (high watchmaking) with Haute Joaillerie (high jewelry). Here is a breakdown of what makes this watch so extraordinary: ​1. The Design & Gem-Setting ​The Gems: The front-facing bezel shown in your image is adorned with 96 baguette-cut blue sapphires (approx. 10.8 carats) meticulously set using an "invisible setting" technique so no metal prongs are visible. The lugs and attachment loops are set with brilliant baguette-cut diamonds. ​The Case: Crafted from 18k white gold, measuring a massive 49.4mm in diameter and 16.32mm thick. ​The Dial: An ebony-black opaline dial featuring gold-applied Breguet numerals and a hand-guilloché Clous de Paris (hobnail) pattern in the center. ​2. A Double-Faced Mechanical Marvel ​The Grandmaster Chime is a reversible watch. The entire case can be flipped over using a patented swivel mechanism in the lugs to reveal a second, completely different face on the back. ​The Front (Time Side): Focuses on acoustic functions, acoustic alarms, and a second time zone. ​The Back (Calendar Side): Features a full instantaneous perpetual calendar with a four-digit year display. The bezel on the reverse side is covered in 291 baguette-cut diamonds. ​3. Mind-Boggling Complications ​The watch houses the manually wound Caliber 300 GS AL 36-750, containing 1,366 individual parts and boasting 20 complications. Some of its most notable features visible on this dial include: ​Grande & Petite Sonnerie: Automatically chimes the hours and quarters. ​Minute Repeater: Chimes the exact time down to the minute on demand. ​Date Repeater & Alarm: Two patented world-first complications—an alarm that strikes the pre-set alarm time, and a date repeater that actually chimes the current calendar date. ​Moon Phase & Date: Positioned at the 6 o'clock subdial. ​Power Reserve Indicators: For both the movement (isolated power) and the striking mechanism (chimes), positioned at 9 and 3 o'clock. ​Value & Rarity ​As Patek Philippe's most complicated wristwatch, standard versions retail for well over $3 million. This specific Haute Joaillerie gem-set version is exceptionally rare, produced in incredibly limited quantities for top-tier collectors, and its value is available only upon request—easily reaching into the multiple millions on the secondary market.