[dropcap size=small]T[/dropcap]here have been enough sapphire-cased watches since Richard Mille created the first one in 2012 that it’s safe to say they’re an official trend. But Greubel Forsey claims that its Double Tourbillon Technique Sapphire, unveiled this year exclusively for the US market, isn’t a simple case of bandwagon-hopping, but merely the apex of a collection to offer a better view of its movements in the first place.

Now, in addition to the dial-less nature of Double Tourbillon Technique watches, a completely transparent caseback, band, bezel,front, lugs and even crown, will allow wearers to view the 396-part movement from virtually any angle. It may not be a novel idea (and Greubel Forsey itself has got creative with sapphire before, by making bridges out of it) but it is always an impressive feat, considering sapphire is frustratingly difficult to work with. Despite its diamond-like hardness and scratch-resistance, the slightest error in machining can cause the whole block to shatter.

(RELATED: 5 Watch Leaders On People Who Inspire Them.)

Those unfamiliar with the original Double Tourbillon Technique (in platinum) should know that it has 120 hours of power reserve and its twin tourbillons, which rotate at different speeds and angles, make for a movement so precise it won the International Chronometry Competition in 2011. Combine that technical feat with beautifully finished components and you will agree that this is a calibre worth showing off.