Montblanc’s new Grand Tourbillon Heures Mystérieuses celebrates the 150th anniversary of the Minerva’s founding and the inauguration of renovated manufactu re in Villeret. These timepieces will be available in unique versions in platinum and editions of eight in either white or rose gold.

One feature impossible to overlook is the Tourbillon, which revolves around its own axis once a minute; including the balance, it comprises 95 individual parts and weighs in at 1.010 grams. The Tourbillon cage, which measures 18.4 mm in diameter, contains a large balance with a diameter of 14.5 mm; it has a high moment of inertia of 59 mgcm2 and the classical frequency of 2.5 Hertz (18,000 bph). Particularly noteworthy are the three movable compensating weights with the Minerva arrow, which can be pushed to and fro on the curved arc of the Tourbillon cage to obtain perfect equilibrium.

The steel Tourbillon bridge is a miniature work of art and takes the form of two horizontal, overlapping figures of eight, which are also symbols of infinity. All the steel parts in the bridge and cage are cut from solid pieces of metal and then painstakingly shaped, chamfered and polished by hand, a job that takes three weeks for each Tourbillon.

The pendules mystérieuses created a sensation when they first appeared, its hour and minute hands appeared to float freely in mid-air. The same is used here, except that the background of the dial is not transparent but has a mirror finish. In front of this rotate two highly transparent, wafer-thin sapphire glass discs, one embossed with the hour hand, the other with the minute hand. As precious as the movement are solid gold dials with guilloche decoration for the gold watches and custom-made dials for the unique models in platinum.