A diamantaire is a person who specializes in evaluating raw diamonds and cutting them into the most appropriate shape for the characteristics of the stone and the desired setting. This term is also more generally used to refer to people who work in the diamond industry, especially if they are leading members of diamond companies; they may not directly interact with stones for the cutting process, but they do evaluate and acquire stones. People involved in this field usually learn through on-the-job training, starting as apprentices and gradually taking on more advanced tasks.
Diamantaires usually are knowledgeable about other gemstones, as well as diamonds, and can be involved in assessment and cutting of a variety of stones. Their work starts with looking at raw stones. The stone may need to be cleaned and a small facet is cut to get a window into the stone. This is used to get an idea of the stone's quality. The stone will be graded and the diamantaire can start to consider how the stone can be cut. Half the weight or more may be lost in the process of developing a raw stone into a finished gemstone.
The diamantaire can work a stone whole, but more commonly, raw diamonds are cut into smaller stones and developed individually. A cutting plan must be developed. Some stones can be cut in accordance with very basic and generic guidelines. In other cases, the cutting must be customized to the stone. The goal is to create the correct arrangement of facets, allowing light to bounce within the stone and highlight its best features. The diamantaire must consider issues like inclusions within the stone that might make cutting difficult or degrade its quality.
The actual process of cutting includes working with a variety of tools to slowly reveal the facets of the stone. When the stone is fully cut, it can be polished to prepare it for sale. In some parts of the diamond industry, the diamantaire also engraves the stone with a code providing information about its origins. This practice is used by companies participating in programs certifying diamonds as conflict-free, indicating that they were not used to finance wars and other illegal activities.
The diamantaire is a skilled artisan, familiar with quickly evaluating stones and deciding on the best way to handle them. The work also requires a high level of aesthetic training, including familiarity with changing fashions in jewelry. Historically, the focus of gemstone cutting was on preserving as much of the stone as possible. Today, it is on showcasing the natural beauty of the stone and may involve innovative patterns of facets to make a stone stand out from other pieces.
In the sense of a diamond industry professional who does not actively cut stones, the diamantaire is responsible for acquiring stones for a diamond company, discussing plans for cutting and displaying them, and interacting with customers who wish to buy diamonds.