Coal has been dug in Hasle Lystskov since the mid-1800s. In the process, a lot of clay was also obtained, which was used for tiles, among other things. However, there was no real factory of clay products until 1889, when the Hasle Klinke- og Chamottestenfabrik was established. But when that company opened, it needed large quantities of clay. The old clay pits are now beautiful lakes. Pyrite Lake is the largest of the ancient clay tombs.
In addition to Lake Pyrit, there is also Lake Sapphire and Lake Emerald in the immediate vicinity, although these are smaller and surrounded by trees. In these three clay pits, clay was dug from around 1900 to the end of the 1980s for use in the manufacture of clinker, pipes, etc.
Lake Pyrit was previously referred to as Sorthat Lergrav, however it was thought that it should have a name change as the other lakes in the area have some nice names. It was named Pyrite Lake precisely because pyrite (sulphur dioxide, perhaps better known as fool’s gold) is also found in the area.
But in addition to coal and clay, other very interesting things have been found at the lake. On the beach of Lake Pyrit, traces of a dinosaur were found in 2004 and another one in 2010.
If you like to sit with a fishing rod, you are allowed to fish in Lake Pyrit, Lake Sapphire and Lake Ruby without a fishing permit.
But the ravages of time are catching up with Lake Pyrit. Over time, the Baltic Sea’s powerful waves have washed away much of the soil and waste products from the clinker factory between the sea and the lake, so that there are now only about 12 – 15 m left before the sea breaks through. You can’t predict when it will happen, whether it will be months or years, it all depends on how many storms there are in the Baltic Sea. But when that happens, it will have a huge impact on lake life as the freshwater turns to saltwater.