Watch glass made of sapphire crystal began dominating the industry in the 1980s. This material is especially hard and, therefore, scratch-resistant. What's more, sapphire glass lets in plenty of light, thus improving the watch's readability.
Most modern luxury watch manufacturers include sapphire crystal watch glass as a standard feature of their timepieces. The reason is clear: Sapphire is the world's third hardest mineral, behind only diamond and moissanite. As a result, it is extremely scratch-resistant. Moreover, it lets in more light than quartz, mineral, or acrylic glass, making it even easier to tell the time.
While sapphire is a naturally occurring mineral, the sapphire crystal used in watch glass is a synthetic material. Some people even refer to this colorless crystal as "sapphire glass" because it is so transparent.
The watch industry began churning out large numbers of watches with sapphire crystal in the 1980s. Before then, mineral or acrylic glass was the material of choice. Today, many manufacturers also use sapphire crystal for their case backs. There are even a handful of companies producing entire cases out of this clear material.
|Model||Reference number||Price (approx.)|
|Hublot Big Bang Unico Blue Sapphire||411.JL.4809.RT||63,500 USD|
|Blancpain Fifty Fathoms Automatique||5015 1130 52A||11,000 USD|
|Rolex Oyster Perpetual Date||1530||9,400 USD|
|Breitling Navitimer||A23322||4,700 USD|
|Oris Divers Sixty-Dive||01 733 7720 4055-07 5 21 02||1,600 USD|
|Mido Ocean Star Captain V||M026.430.47.061.00||1,000 USD|
|Laco Augsburg 42||861688||380 USD|
|Casio Collection||BEM-111D-1AVEF||70 USD|
Since sapphire crystal wasn't a common watch feature until the early 1980s, there are very few vintage watches with this material. However, there are a few notable models. Rolex was one of the first companies to recognize sapphire's potential and use it in series production. The Rolex Date ref. 1530 and its successor, the Datejust ref. 1630, were among the first timepieces to utilize this scratch-resistant watch glass. Both watches emerged in the early 1970s and are extremely rare today. A stainless steel ref. 1530 costs around 9,300 USD, while the two-tone Datejust ref. 1630 demands about 5,400 USD.
The Submariner ref. 16800 from the late 70s was Rolex's first sports watch to feature sapphire crystal. Like all Submariners, the 16800 is a highly coveted collector's item. However, at only 9,200 USD, it is relatively affordable compared to other Submariner models.
Omega began experimenting with sapphire crystal all the way back in 1932. This resulted in watches like the Omega Marine ref. CK 679, which sells for as little as 2,600 USD today. However, Omega wouldn't use sapphire glass for timepieces in series production until the late 1970s, starting with the Seamaster 120 ref. ST 166.0250. This diving watch is water-resistant to 120 m (12 bar, 394 ft) and changes hands for roughly 3,900 USD in good condition.
There are no vintage examples of the fan-favorite Speedmaster Professional Moonwatch with sapphire crystal. In fact, Omega outfitted this timepiece exclusively with synthetic Hesalite glass until the turn of the millennium. The reason is that this watch was part of NASA's official equipment and the space agency insisted on Hesalite since it doesn't splinter upon impact. However, Omega did introduce a few models with sapphire glass case backs in the 1980s, including the limited edition Apollo XI ref. BA345.0802. You can call this watch your own for some 33,500 USD.
Since vintage models with sapphire crystal are so rare, modern takes on classic vintage timepieces make great alternatives. For example, Breitling has been crafting their iconic Navitimer pilot's watch with sapphire crystal since the late 1990s. Depending on the model and its condition, Navitimer prices range from 2,200 to 39,000 USD.
Storied Swiss watch manufacturer Blancpain has been equipping their classic Fifty Fathoms diving watch with sapphire crystal for years. New editions of the Fifty Fathoms Barakuda and Fifty Fathoms Automatique even feature a sapphire crystal bezel inlay in addition to their sapphire crystal watch glass and case backs. These attractive timepieces change hands for about 11,000 USD.
TAG Heuer also has a long history with sapphire crystal in their Carrera and Monaco collections. This material appears on their Heritage models, such as the Monaco Calibre 11, as well as their classic Carrera Calibre 1887. The latter gets its name from the in-house caliber 1887. You can purchase a mint-condition Monaco Calibre 11 with the blue "Steve McQueen design" for around 4,300 USD. Pre-owned pieces tend to cost a few hundred dollars less. If you prefer the Carrera Calibre 1887, be sure to have between 2,600 and 3,500 USD on hand.
Sapphire crystal watch glass is also a common feature on affordable watches. For example, Casio, Orient, and Victorinox all produce quartz watches with sapphire crystal for around 110 USD. Fans of mechanical watches will find pieces from Tissot, Laco, and Citizen beginning around 330 USD.
Most modern watches worth 1,100 USD or more will come with sapphire crystal. You'll find some exceptions among historically accurate re-releases, such as the Sinn 103 St pilot's chronograph with acrylic glass. This model sells for roughly 1,800 USD new and 1,600 USD pre-owned.
Companies like Hublot, Richard Mille, MB&F, and Cabestan take the concept of a sapphire crystal watch to the next level. Each offers timepieces with cases made of solid sapphire crystal. Most of these models lack a traditional dial, offering an unobstructed view of the heavily skeletonized movement within.
Hublot has the widest variety of sapphire crystal watches. This Swiss luxury watch manufacturer crafts several Big Bang editions out of blue, green, yellow, purple, or clear sapphire crystal. Plan to spend between 43,000 and 80,000 USD on the Big Bang Unico Sapphire chronograph. There's also the Big Bang Tourbillon Power Reserve 5 Days Sapphire in blue or purple. This watch is limited to a run of 30 pieces and requires an investment of over 177,000 USD.
For something even more exclusive, you should turn to Richard Mille. Mille's RM 56-01 tourbillon watch boasts a sapphire crystal base plate for its movement in addition to its solid sapphire case. As a result, the gears, springs, and axles all appear to be floating in midair. Only five copies exist of this timepiece, which sells for an astronomical 2.2 million USD.
Sapphire is an especially hard mineral, with a rating of 9 on the Mohs scale of mineral hardness. This places it just behind diamond and moissanite. The world's largest natural sapphire deposits are found in Sri Lanka, India, Australia, Nigeria, Madagascar, and the USA. While blue sapphires are perhaps the most famous, sapphires can come in any color but red.
However, the sapphire crystal used in watches is synthetic. It's created by melting aluminum oxide powder at 3,722°F (2,050°C) and forming it into a pear-shaped crystal between 1.1 and 1.6 inches (3 and 4 cm) wide. This material is then cut, sanded, and polished using a diamond angle grinder. The final watch glass receives a special anti-reflective coating, usually in the form of a blue-tinged film applied to the crystal. Older watches tend to only have this coating on the crystal's inner side since previous coating methods were highly susceptible to scratches. However, this is no longer a problem in modern watchmaking, and most sapphire crystal watch glass has this coating on both sides.
The main advantage of sapphire crystal is its scratch resistance. However, its hardness also makes it susceptible to hard impacts. Unlike plastic-based watch glass, sapphire crystal watch glass is known to splinter. Furthermore, soft materials like aluminum can leave behind unattractive streaks on the crystal. Luckily, you can easily remove these streaks using a normal pencil eraser.
If you're not sure whether or not your watch has sapphire crystal, there's an easy way to find out: Put a drop of water on the crystal and lift the case at a slight angle. The water will move relatively slowly across sapphire crystal and leave no streaks behind.