Casio's MRG-D5000 will come in a run of only 20 watches worldwide, each with a bezel the company describes as made entirely of blue sapphire crystal.
The material is the engineering problem. According to Casio, sapphire crystal can crack around the screws that normally hold a watch together, so the MRG-D5000 uses the MR-G Multi-Guard Structure, a proprietary design that builds the bezel and case from several separate components joined without screws. Casio says it analyzed how much force reaches the crystal during an impact and shaped the structure around protecting that one material. It also calls the watch the first G-Shock to achieve a shock-resistant structure with blue sapphire crystal components, a claim the release makes without naming a test standard or an impact figure.
The case back follows the same material choice. Casio sets a blue sapphire crystal into the screw-lock back and engraves an individual serial number on each of the 20 pieces. Inside, the module is Gallium Tough Solar, which Casio says is built for durability under intense light and efficient charging.
MR-G is the flagship collection of the G-Shock brand, launched in 1996, and Casio frames the line with a "Breaking Ground" philosophy.
Casio announced two other blue sapphire models alongside it. The MRG-B5000SA is a second MR-G, with two-carat, facet-cut blue sapphire crystals at the top and bottom of the case, a bezel in a super-hard alloy and blue arc ion plating on both case and bezel. The GMW-B5000SB is a full-metal G-Shock with blue sapphire crystal stones set at four points on the front of the bezel.
The release lists no price or on-sale date for any of the three watches. In the two companion models the sapphire sits alongside metal rather than replacing it, while only the MRG-D5000 asks the crystal to do structural work. That is why its 20-piece run reads as a demonstration of the housing as much as a luxury object.
