(IDEX Online) - A necklace featuring a huge 93.94-carat Paraiba tourmaline is to be auctioned by Sotheby's Geneva, with a $1.44m to $2.44m estimate.The Blue Lagoon comes from Mozambique and is described as "slightly greenish blue, richly saturated with very fine clarity".It has been set by Geneva-based Adler Joailliers in a diamond lariat necklace with 36.50 carats of marquise cuts,13.95 carats of pear-shaped diamonds and 14.75 carats of brilliant-cut diamonds.It will lead the Magnificent and Noble Jewels auction on November 8. Tourmaline was first discovered in the 1500s in a variety of colors. But vivid blue/green examples of the gemstone were only discovered in 1989. They are called Paraiba after state in Brazil where they were first found and can command significantly higher prices than diamonds, carat for carat.Pic courtesy Sotheby's.