Azure Lake, Poland Stock Photography

Colourful lakelets (Polish Kolorowe Jeziorka) is the name of three (sometimes four) artificial lakes located at former mines at the slope of Wielka Kopa mountain in Rudawy Janowickie in Sudetes Mountains, Poland. The biggest one and the eldest is the Purple lakelet. The second biggest is Azure Lakelet, with the smallest being the Green Lakelet. These places were mined from 1785 to 1925 for pyrite. The Purple lakelet owes its colour to chemical composition of its banks and bottom which are abundant with iron compounds, mainly pyrite. The pond is filled with water solution of sulphuric acid (pH = 3), therefore it is highly recommended to avoid contact with water. Beside the Purple Lakelet there is a smaller hollow, which occasionally is filled with water falling from the pond above and is called the Yellow Lakelet. The colour of Azure Lakelet, also called Blue or Emerald is due to the presence of copper ions. The water is clean, but cold even in Summer. Green Lakelet, also called Black Pond, same as Azure Lakelet owes its colour to copper compounds. Depending on rainfall, it temporarily disappears.