Union Pear has been producing color gradation pearl necklaces since 1990. The “Shikisai” high-quality color gradation necklace series was identified a genuine product by the Pearl Science Laboratory in 2019, and trademark registration has been obtained in 2020. The main feature of Shikisai necklaces is that they are made of only naturally-colored pearls. As no irradiated or otherwise dyed pearls are used, the series is gaining popularity for the natural beauty of the pearls. It is a product that only Union Pearl can make for being one of the companies that handle a large volume of pearls while realizing mass production which cannot be achieved any other way. When lining up pearls to create a necklace, a subtle difference in color can have a great impact on the beauty of the gradation. Although the company has 200,000 to 300,000 pieces of pearls in stock at all times to select from, artisans may stop the work and reassemble the necklace with a different color gradation in case they cannot create a perfect gradient. Skilled artisans are committed to precision and to making products look their most beautiful without compromise. In three years since its launch, the product has sold a total of 10,000 pieces and has been beloved by customers from all over the world.