An in-depth look at the history of watches and sapphire crystals with a sapphire processing specialist

Sapphire has been used in watchmaking for about a century. Its composition is mainly created using high-tech techniques, and it has become widely used in modern parts. For example, Chanel released a model in 2020 that was the first to feature sapphire in the bracelet.

Serge Maillard, publisher and editor-in-chief of Europa Star, uncovers the secrets of this exceptional material through an interview with Anthony Schwab, director of Econorm, an innovative company specialising in the processing of sapphire for watches.

A century of sapphire use

　The use of sapphire in watchmaking has expanded from crystals to cases and bracelets, thanks to the existence of companies specializing in the production and processing of sapphires. Econom, Sébal, Erma Stettler, and Comadur (Swatch Group) are just a few examples of companies active in this field.

　Sapphire first appeared on the watchmaking scene about a century ago. Jaeger-LeCoultre began using sapphire crystal as early as 1929 to protect the dial of its "Duoplan" watch, which featured an ultra-compact movement. Since 1966, Century has established the core technology of sapphire watches with its "Megalith" case structure, which integrates two types of sapphire. In 1980, watchmaker Vincent Calabrese designed a watch with a sapphire case for Corum. Its transparency allowed the unique movement of the "Golden Bridge" to be admired.

　Since then, the quest for transparency in watchmaking has accelerated the industry's adoption of sapphire. For example, in 2020, Chanel introduced the world's first sapphire bracelet model for its J12. And in 2021, Hublot released the spectacular Big Bang Integral Tourbillon Full Sapphire.

Sapphire and Ruby, cousins

"To make sapphire processing more innovative and sophisticated, we must first have a thorough understanding of the raw material," emphasizes Anthony Schwab, president of Econom, which has workshops in Gams and Saint-Imier, Switzerland.

　Sapphire is actually a type of corundum, the red variety of which is known as ruby. Sapphire and ruby ​​are therefore "cousins," and both are common in watchmaking. Sapphire is second only to diamond in hardness and is known to be difficult to machine.

　Corundum is naturally colorless, but the presence of impurities can cause it to have a variety of colors. Impurities such as iron and titanium give it a blue color, which is the most common color found in nature. The main sources of sapphire are South Asia and East Africa.

　However, synthetic sapphire is mainly used in watchmaking, and most of it is produced using a method developed by Auguste Verneuil in 1902. The Verneuil method (flame fusion method) involves melting alumina powder with a hydrogen flame and creating sapphire drop by drop at temperatures above 2000°C.

Pioneering processing

“Faced with competition from Asia, our partners in the Jura, Timsaph and Sébal, have started producing 100% Swiss sapphires, focusing on local supplies and further refining their techniques,” explains Anthony Schwab.

　Since 2018, Econom has been using this raw material to produce "functional sapphires" for the watchmaking industry. These benefit from advanced treatments such as anti-reflective coating on both sides, UV filtering, colorlessness, anti-static properties, and water resistance. In fact, untreated sapphire reflects so much light that it makes the dial difficult to see clearly.

　A company manager explains:
"Functional sapphires are designed to benefit both the wearer and the watchmaker. For example, their anti-static properties prevent dust accumulation during assembly and protect the watch's accuracy from the effects of static electricity. Their UV filtering properties preserve the color of the dial, ensuring that customers receive the product they selected. And in see-through watches, they prevent premature deterioration of the oil, thereby eliminating the need for additional maintenance services."

　The company supplies not only crystals, but also sapphire dials, cases, and movement components such as gears.

Price Issues

　Econom works in research and development with the Swiss Federal Laboratories for Materials Science and Technology (Empa). Each year, the company produces over 150 million sapphire crystals, priced from under 10 Swiss francs to several thousand, depending on the complexity of the process (for example, Econom created the domed crystal for MB&F's first women's watch, the Flying T).

　The company, which employs around 60 people, is not limited to watchmaking and its functional sapphires are also used in the medical, automotive and aerospace sectors, as are many Swiss subcontractors.

"Most of the sapphire crystal used in the Swiss watch industry today comes from Asia," says Antony Schwab.

　He continues, "We hope that this will change, for example, as the Swiss watch industry moves more upmarket and increases average unit prices. Demand for our high-tech sapphire crystal is growing, which is unfortunate (given the current situation regarding the sourcing of sapphire for Swiss watches), as sometimes the difference in unit price is only a few francs."