Greubel Forsey GMT Black (In Titanium Case Treated with Black ADLC)

Launched in 2015, the GMT Black is a unique edition of 22 pieces of its GMT timepiece in titanium treated with black ADLC.

For more than a decade Greubel Forsey has been introducing highly creative ideas, each with a distinctive character. Here, for the second time, the company explores the contemporary Timepiece with a titanium case treated with vacuum deposited ADLC (amorphous diamond-like carbon). In addition to its striking appearance, this deep black coating gives the watch a surface hardness significantly greater than natural titanium.

With the movement’s main plate and bridges also treated in black, the palette of colours is more restrained. This helps to bring out the contrast between the different surface finishes in each component’s decoration. However, relatively stronger colours are used to subtly highlight all indicators of time and technical information. The various dials and indication zones appear to be floating in the space around the terrestrial globe, evoking the night sky with the stars twinkling in their eternal orbits.

Technical details
Model: GMT
Unique edition
22 pieces in black ADLC titanium
Mechanical hand-wound movement with patented tourbillon Calibre GF05
2nd time zone GMT display • Tourbillon 24 Secondes • titanium rotating globe with universal time display • 24 time zone worldtime display • summer time indicator • worldtime disc with summer time zones • day-and-night indicator • power-reserve indicator • hour and minute display • small second indicator • GMT pusher • equatorial synthetic sapphire crystal lateral window

Diameter: 36.40 mm
Thickness: 9.80 mm

Number of parts
• Complete movement: 437 parts
• Tourbillon cage: 86 parts
• Weight of the cage: 0.39 g
Number of jewels: 50; Olived-domed jewels in gold chatons

Power reserve: 72 hours
Barrels: Two coaxial series-coupled fast-rotating barrels (1 turn in 3.2 hours), one of which is equipped with a slipping spring to avoid excess tension
Balance wheel: Free sprung variable-inertia balance with gold mean-time screws (10 mm diameter)
Frequency: 21’600 vibrations/hour

Balance spring
• Phillips terminal curve
• Geneva-style stud

Main plates: Nickel silver, frosted and spotted, bevelled with countersinks and straight-grained flanks, black chrome treatment

• Nickel silver, frosted and spotted, bevelled with countersinks and straight-grained flanks, black chrome treatment
• Gold plate engraved with the individual number
• Flat black polished steel tourbillon bridge, hand-bevelled

Tourbillon cage
• Inclined at a 25° angle, 24-second rotation
• Cage pillars in Avional
• Titanium cage bridges
• Gold counterweight

• Involute circle profile
• Conical gearing with corrected profiles

Hour and minute
Small second
72-hour power reserve on a sector
2nd time zone GMT indicator
24 time zone worldtime display
Rotating titanium globe with universal time display
Summer time indicator
Day-and-night indicator

In black ADLC titanium with convex synthetic sapphire crystal
Diameter: 43.50 mm
Thickness: 16.14 mm
Transparent back with asymmetrical convex synthetic sapphire crystal
Polished bezel and centre band with hand-finished straight graining
Lateral window with shaped synthetic sapphire crystal
Three-dimensional, variable geometry-shaped lugs
Black ADLC titanium pusher with raised polished engraving “GMT” on a hand-punched background
Raised polished engraving “Greubel Forsey” on a hand-punched background
Engraved individual number on the caseback
Gold security screws
Water-resistant: 3 atm – 30 m – 100 ft (standard NIHS 92-20/SN ISO 22810:2010)
Crown: Black ADLC titanium with engraved GF logo

Principal hour-minute dial: in gold, frosted, black treatment, Hour-ring in gold, black treatment
Gold power-reserve sector
Gold small second dial
Gold GMT indicator
Applied gold Greubel Forsey logo

Hour and minute in polished gold, with Super-LumiNova
Small second in polished gold and power-reserve in polished gold
2nd time zone GMT indicator, red triangle

Strap and clasp
Hand-sewn black rubber strap
Black ADLC titanium folding clasp, engraved with the Greubel Forsey logo

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