RAPAPORT... A 17.43-carat Kashmir sapphire previously owned by aEuropean noble family will go on sale at Bonhams later this month. The cushion-shaped, vivid-blue stone, which dates to thelate 19th or early 20th century, will lead the April 30sale in London, the first time it has appeared at auction. It is expected to fetch GBP 300,000 to GBP 400,000 ($391,080 to$521,440). "Sapphires hailing from Kashmir are among the most highly prizedgems for serious connoisseurs," Emily Barber, director of jewelry at BonhamsUK, said last week. "After the discovery of the mine in the high Himalayanmountain region of northwest India in 1881, the majority of mining activitytook place during the following decade, after which the supply was essentiallyexhausted. This makes them extremely rare." The sale will also include a step-cut, 9.07-carat, F-colordiamond ring, which has the potential for VVS1 clarity. That piece is valued atGBP 250,000 to GBP 350,000 ($325,900 to $456,260). A transformable diamond andsapphire necklace by designer Grassy will also go under the hammer. The articulatedcollar can be worn as is, or in one of four other ways: the 34.59-caratsapphire detaches and can function as a ring; the entire center plaque of thenecklace can be removed and worn as a clip; and the detachable plaque clasp canbe worn either as a clip or in the center of the necklace. It carries a presalevalue of GBP 120,000 to GBP 180,000 ($156,430 to $234,650). In addition, Bonhams will auction a ring featuring astep-cut, 22.02-carat, Colombian emerald sitting on a mount formed by twomarquise and brilliant-cut diamond honeybees and two brilliant-cut diamondleaves. The jewel, signed by both Tiffany & Co. and designer JeanSchlumberger, was part of the collection of artist Andy Warhol. It is estimatedat GBP 65,000 to GBP 85,000 ($84,730 to $110,810). Image: The 17.43-carat Kashmir sapphire. (Bonhams)