Until recently, only emerald, ruby and sapphire were officially called precious gems. Everything else was called semi-precious. The precious categorization is a reference to value: a really fine ruby, emerald or sapphire can be priced higher per carat than a diamond. Sapphires are extremely hard and durable, so they will last a forever in a piece of jewelry, and rubies and emeralds are extremely rare. There are some rare finds among the so-called semi-precious gems that can be priced higher than the big three, but in general, a fine ruby, sapphire or emerald will hold its value and command more respect and a higher price than other gemstone. That is the reason Art Deco jewelry – heavy on the big three – is usually prized over other period jewelry. Top watch brands, mindful of this, use emerald, ruby and sapphire in their most important jewelry watches, as the big three below demonstrate – from Cartier
, Backes & Strauss and Van Cleef & Arpels.

Cartier Tourbillon Mysterieux Azure

The Tourbillon Mysterieux Azure Pendant watch combines high jewelry, high watchmaking and mystery-watch technology, all Cartier specialties, in a beautiful piece that is both wearable and collectible. The star of the show is a spectacular 25.93-carat Sri-Lankan sapphire hanging from the bottom, chandelier style. It is removable – but why would you remove it? Fine sapphires are also used to form the tips of the butterfly wings, between rows of diamonds that radiate from the center. The movement, the Cartier-made tourbillon Caliber 9463 MC, is suspended between sapphire crystals. It is a unique piece that took 2,050 hours of work. Price upon request

Backes & Strauss Piccadilly Princess Royal Emerald Green

This million-dollar, one-of-a-kind watch is called the Piccadilly Princess Royal Emerald Green. It is set with 245 Zambian emeralds totaling 31.91 carats in 10 different cuts, sourced from Gemfields, which owns the world’s largest emerald mine, the Kagem in Zambia. The watch is the third in a series of five unique watches that celebrate the 225^th anniversary of Backes & Strauss, the world’s oldest diamond and gemstones company. One of the two previous editions was set with colored diamonds and the other, with sapphires.

Ruby Secret Watch

It took several years for the jewelers at Van Cleef & Arpels to collect the 155 perfectly color-matched rubies used to create this unique piece, and another year to make it. There are 151.25 carats of rubies in total, each custom cut to fit the composition, mostly in oval and round shapes. The three rows of rubies are separated by round and square diamonds, all set in white gold. Time can be read by lightly pushing on the rubies at one side, releasing a secret drawer that is integrated into the bangle. The drawer is engineered to one hundredth of a millimeter tolerances so that it slides in and out under the girdles of the gems above it without ever touching them.

Graff Disco Butterfly

I couldn’t resist adding this example. Graff’s Disco Butterfly employs rubies to express one of the strongest trends in ladies’ watches this year – animation. The marquise-cut rubies on this dial, which are set to resemble butterfly wings, are position on disks that rotate on their axis and at the same time, around the dial. The movement is generated by the wearer’s wrist, just like an oscillating weight in a self-winding watch. Sapphire and emerald options are also available. The 38mm case is white gold, and it contains a quartz movement.