Sapphire is one of the most popular gemstones, known for its deep blue color and impressive hardness. It is the birthstone for September and is often used in engagement rings, necklaces, earrings, and bracelets. But, have you ever wondered how a rough sapphire stone is turned into a sparkling gemstone? In this post, we will discuss the process of sapphire gemstone cutting, from rough stone to polished gemstone.

Step 1: Obtaining a Rough Sapphire

The first step in the process of sapphire gemstone cutting is to obtain a rough sapphire stone. Rough gemstones come in all different shapes depending on the geological environment they are found in, and they are unlikely to be completely clear. Inspecting the rough sapphire for color and any imperfections is done by immersing it in water or rubbing a bit of oil on it. 80% of the mine's cost is covered by 20% of its production, which is why finer quality gemstones attract a higher price.

Having the ability to envision the final outcome of a sapphire after it has been cut and polished by simply examining a raw sapphire is an exceptional talent. The process of selecting the appropriate raw sapphire and purchasing it at a reasonable price is a critical decision that can make or break one's success. If one succeeds, they can expect significant rewards, but if they fail, they will lose their investment. While this determination may be straightforward in certain situations, it is usually a challenging one. The successful merchant is the one who manages to win more often than lose in this game. When making this decision, several factors must be considered, such as the size of the raw sapphire, its shape, inclusions, splits, color, and color zoning.

Step 2: Pre-forming the Sapphire

The next step is to preform the rough sapphire stone. Natural sapphires are colored by color patches or color banding, and the gem cutter has to ensure the color patch is placed suitably to reflect the expected color throughout the sapphire once we finish cutting and polishing. The cutter also has to attempt to place inclusions along the girdle line as this is where it will be least visible. Shape and cut depending on the shape of the rough gemstone, inclusions, and the color patches. Appropriate cutting angles should also be placed in the pavilion in order to achieve total internal reflection, meaning avoiding windowing and extinctions. The cutter will then proceed to pre-form the stone, during which any inclusions that affect the durability of the stone are removed. Following this, the rough sapphire stone is shaped according to its shape and cut.

Sapphires possess a unique optical characteristic known as pleochroism, which causes them to display varying colors depending on the angle of observation. It is crucial to cut the rough sapphire in the correct direction to achieve the optimal color outcome. In the gem mines of Rathnapura, Sri Lanka, pleochroism is referred to as "Waakkuwa" in the local slang.

Step 3: Faceting and Polishing the Sapphire

The final step is to facet and polishes the stone. Colored gemstones, including sapphires, are cut for color first, followed by brilliance. The mixed cut is the most commonly employed faceting method in the sapphire cutting industry. This technique involves cutting the top facets using the brilliant cut method, while the bottom facets are created using the step cut method. This approach is widely considered to be the optimal cutting technique for achieving the finest color and brilliance in a sapphire. The cutting angle of the pavilion makes the gemstone sparkle by reflecting light back to the eye, and the ideal cutting angle of the pavilion differs from gem to gem. Step facets are usually used on the pavilion of oval and cushion shapes to maximize the appearance of color, while brilliant facets are placed on the crown to maximize brilliance and sparkle. A skilled gem cutter can preserve over 50% of the weight of the rough stone during the cutting and polishing process. However, the precise percentage can vary significantly depending on the unique characteristics of the rough gemstone being cut.

In conclusion, sapphire gemstone cutting is a complex process that requires knowledge, skill, and experience. The cutter has to take into account the shape of the rough sapphire stone, its inclusions, and color patches to determine the cut and shape of the final gemstone. Faceting and polishing the sapphire gemstone is the final step that maximizes the color and brilliance of the stone. If you are looking to purchase a sapphire gemstone, knowing about the cutting process can help you choose the right stone that best suits your preferences.