Ilmakiur is a barometer made of stone. The stone barometer changes its color depending on the advancing weather and is used for predicting the weather. Ilmakiur has been written about in many books from the 1800s. The stone barometer was discovered in Finland and is located in the northern part of that country. Ilmakiur is also called the "weather stone".
Ilmakiur turns black or grayish when it is going to rain. The stone shows white spots when it is going to be fine weather. In the 1800s it was believed the rock was a fossil made of clay, ammoniac, rock-salt and saltpeter. The stone was thought to attract dampness from the atmosphere. If the weather was good Ilmakiur would dry out and the salt would appear as the white spots. Modern scientists say the rock is a fossil of potassium nitrate and rock salt.
- Fessenden, Thomas Greene (1835), The New England Farmer and Gardener's Journal, Volume 13. Page 142.
- Kibblewhite E.J. (1892), English mechanic and world of science. page 585.
- Curiosities for the Ingenious. : selected from the most authentic treasures of Nature, Science and Art, biography, history and general literature, Second Edition, printed for Thomas Boys, Ludgate Hill. Page 175., 1822
- Lee Albert (1976), Weather Wisdom, Facts and Folklore of Weather Forecasting. Congdon & Weed, Inc. page 27