Combining jewellery and watchmaking: Discover the world and craftsmanship of diamond-set watches

Diamond-set watches are special creations that combine the splendor of jewelry with the exquisite craftsmanship of watchmaking. From the procurement of rare stones to the exquisite cutting and setting, and the selection of materials, they are packed with the handiwork and ingenuity of skilled artisans. In this article, we will introduce the appeal of the diverse diamond-set watches produced by each brand and the technology that supports their brilliance.

The brilliance of diamonds. The fusion of jewellery and watchmaking

　Diamond-set watches combine the splendor of high jewelry with the technical sophistication of watchmaking. Here, we explore the technical and aesthetic considerations involved in decorating a watch with diamonds, from sourcing rare stones to invisible settings.

Are diamonds really rare?

　Diamonds are generally considered to be extremely rare, but in fact, a large amount is mined worldwide, and although there are only a limited number of high-quality rough stones suitable for jewelry, there is no extreme shortage of supply. However, in the case of watches, the value of diamonds that have been processed into jewels far exceeds the price of the rough stones themselves. This is due to the effort required for careful selection and processing, the sophisticated setting techniques, and the added value of the brand.

How a diamond is born

　Diamonds were formed deep in the Earth's crust, approximately 145 to 640 km deep, approximately 9000 to 30 billion years ago. Under extreme heat and pressure, carbon atoms bonded together to form the hardest natural substance on Earth. Volcanic activity then transported them closer to the Earth's surface, but many were lost in the process. The surviving stones were trapped within the host rock as the magma cooled, forming deposits known as kimberlite pipes.

　India was once the main producer, but South Africa, Angola, Botswana, etc. later emerged. The quality and production volume vary greatly depending on the region, and on average, 200 to 250 tonnes of ore must be processed to obtain one carat of jewelry quality.

From rough to brilliance: The five C's

　A rough diamond lies dormant, like a cloudy piece of glass, with its hidden light. It is only when it is polished and cut that it begins to emit its dazzling sparkle and charm. The standards for measuring this beauty are the five "Cs" spoken of in the world of watches and jewelry.

　First, carat. It is a unit of weight, with 1 carat equaling 0.20g. The word comes from the carob tree, whose seeds have a uniform weight. In the case of watches, the number of stones is more important than their size, and pave settings, in which small diamonds are densely packed together, are preferred.

　Next is the cut. This refers to the shape of the stone. The brilliant cut, which maximizes light reflection, is the standard, but the baguette cut, which has a more subdued sparkle, is also popular. This tends to have a higher carat weight in theory, as less of the stone is cut away.

　Clarity and color refer to the degree of transparency and color. Most stones have inclusions, but if they are small they are hardly visible to the naked eye. If the color is consistent, the difference is hard to tell, and if set in a white metal, they appear even more colorless. Luxury brands often choose stones with a clarity of VVS2 or higher and a color that is almost colorless.

　The last step is certification. Large diamonds are evaluated and stamped by an appraisal agency, but small diamonds are not. However, without exception, they must comply with the Kimberley Process and be non-conflict diamonds.

Setting techniques

　Once the stones are aligned, they must be set by a skilled craftsman. For brilliant cuts, holes are drilled and the surrounding area is set with prongs. In some cases, the setting process can be more expensive than the rough stone itself.

　The Ulysse Nardin Blast Tourbillon Sparkling has an appearance reminiscent of cracked ice, with baguettes and specially shaped stones fixed in place with an "invisible setting" that hides the metal.

Diamonds in the spotlight

　While many diamond-set watches are derived from plain models, there are also designs that feature diamonds as the main focus, such as Jacob & Co.'s "Billionaire" collection. The case and bracelet are integrated, and the stones are large and uniform in color. Yellow diamond models are also available.