Franck Muller 5850MC “Master Calendar” – 18K Yellow Gold

Ref. 5850MC | Automatic | Box & Blank Papers | 18K Gold Buckle

A beautiful example of the Franck Muller Tonneau Curvex Master Calendar, presented here in full 18K Yellow Gold with box and papers (warranty card unfilled). This is one of the most desirable 5850-series dress watches due to its elegant proportions, substantial gold weight, and classic Master Calendar layout.

Movement

The watch uses Franck Muller’s modified automatic calibre — based on a high-grade ETA ébauche, professionally reworked by Franck Muller with their own calendar module, finishing, and regulation.
This keeps servicing practical and affordable, while still delivering the complication and character the brand is known for.

Reliable. Easily serviceable. Proper watchmaking.

Why This Watch Is Special

• Solid 18K Yellow Gold Case — original Japanese listing confirms a total weight of 80g, with approximately 60g of pure gold content after accounting for movement, crystal, etc.
  • Gold value alone ≈ £4,000 at today’s rates.
  • A genuine hedge piece — you’re wearing a precious metal asset.

• Master Calendar Complication — Day, Date, Month beautifully laid out on a silver guilloché dial.

• Iconic Tonneau Curvex design — 32 × 45 mm wears perfectly as a modern classic.

• Box & Papers — original box included, warranty card blank (common for Japanese dealers).

• 18K Yellow Gold Buckle — factory original.

• New Leather Strap — original CITES-restricted strap removed (standard practice).
  The original exotic straps cannot legally be exported, hence the replacement.

• Strong Condition — light wear marks consistent with age, nothing major, dial is superb, case edges remain clean.

This has all the hallmarks of a future-collectible, with built-in precious metal value protecting your downside.

Full Specification

• Brand: Franck Muller

• Model: Tonneau Curvex Master Calendar

• Reference: 5850MC

• Case: 18K Yellow Gold

• Case Size: 32 × 45 mm

• Dial: Silver guilloché

• Movement: Automatic, FM-modified ETA base with Calendar module

• Strap: New quality leather strap

• Buckle: Original Franck Muller 18K Yellow Gold

• Box: Yes

• Papers: Included

• Weight: 80g total (approx. 60g gold)

Why Buy from Fine Watch Club

• 12-month movement warranty

• Fully authenticated and inspected

• 14-day no-nonsense return policy

• Viewings available by appointment (24 hrs notice)

• Worldwide shipping

• Trusted UK dealer — hundreds of high-end watches sold

Price

£7,500
A very fair price considering the gold content, the complication, and the full presentation set.