Langesundsfjord

The Langesundsfjord (Norwegian: Langesundsfjorden), also known as the Breviksfjord (Norwegian: Breviksfjorden), is a stretch of fjord from northern Skagerrak, between the islands of Sandøya, Bjørkøya and Siktesøya in Porsgrunn municipality and the mainland of Bamble municipality, in Telemark county in the southeastern part of Norway.

The fjord stretches from the strait Langesund until Brevik, where it separates into the Frierfjord and the Eidangerfjord. In the mediaeval period the fjord was named Grenmar, after the grener people who lived here and mar which was Old Norse for sea. Later, well into the 1700s, the entire stretch from Langesund gap and up to Skien was referred to as Langesundsfjord.

Langesundsfjorden is especially noted for the discovery of fluorescent minerals. Many of the minerals found here are relatively rare. Commercial quarrying for decorative stone started in the late 1880s. In 1881, Diderik Cappelen (1856-1935), first found Cappelenite in Langesundsfjorden. Cappelenite, which he discovered in small veins within Nepheline syenite pegmatite, is a rare yttrium-barium borosilicate. It is found in the form of greenish-brown hexagonal crystals.

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