Corum Golden Bridge Tourbillon with Sapphire Bridge

This year, CORUM treats its iconic bridges collection in an extremely innovative way by focusing on the baguette movement with its tourbillon escapement.

The brand accomplished a rare technical feat as the bridge of the CO213 movement – normally entirely made of 18K solid gold – is replaced on the level of the tourbillon carriage by a transparent sapphire component.

One of the major difficulties involved in this operation lay in the necessity of ensuring the smooth coexistence of two materials with such different degrees of hardness, rigidity and dilatation coefficient: sapphire and gold.

The tensions in play are even stronger because this is a baguette-type movement, and the difficulty that had to be surmounted is all the greater because the sapphire bridge is a mere 0.6 mm thick.

One of the ends of the sapphire plate has been screwed to the gold bridge in the usual way, while the other has been cut to form a sharp tip and is simply nested in the second part of the gold bridge, which is specially machined to form a V shape.

Within this new configuration, the tourbillon carriage of the latest Golden Bridge model is now held by a transparent crystal part that is perfectly visible and more airily light than ever. It thus affords a view of its upper bridge shaped like the Corum key emblem, along with all the mobile parts of its silicon escapement.

The entirely guilloché solid gold dial is placed behind the movement rather than in front as is generally the case. It is openworked to ensure that Caliber CO213 is also visible through the back of the watch.

The case of this Golden Bridge Tourbillon model is a study in transparency enabling one to admire the ethereal movement from either side of the case.

No less than four sapphire crystals are thus required to build a case that is watertight to 30 meters and looks very much like a display showcase housing a precious object.

Such an exceptional model is naturally issued in an extremely limited production run: only 10 in white gold and 15 in 18K red gold will be offered to collectors and devotees of this exceptional collection.

Technical details

Model: Corum Golden Bridge Tourbillon
Reference 213.150.55/0002 GK12

Movement
Calibre CO213
Mechanical baguette movement, hand-wound by a stem at 6 o’clock
Tourbillon with Silicon escapement, sapphire bridge
Slipping spring mechanism
Variable inertia balance wheel
Frequency: 2.66Hz, 19’200 vibrations/hour
22 Jewels
18kt red gold plates and bridge
Power reserve of 40 hours

Functions
Hours, minutes, tourbillon

Case
Dimensions: 34 x 51mm
Tonneau-shaped case made of 18K red gold 5N
Polished and satin-finished surfaces
Fluted crown at 6 o’clock decorated with CORUM key
Sapphire crystal open back cover under the movement
Caseback engraved with CORUM logo
Glass: Sapphire crystal
Water-resistance: 99 feet / 30 meters

Dial
Dial in gold 18K, guilloche by hand
Applique hour indexes
Red gold 5N skeleton hour and minute baton hands

Strap
Black crocodile leather strap, hand-stitched
Buckle: 18K red gold 5N tongue buckle