It is believed that during thunderstorms they are hurled to the earth with lightning. A person killed by lightning is struck by a thunderbolt carried by the lightning.
Another belief is that a thunderbolt is created when lightning strikes the earth. Thus thunderbolts are only found in places where lightning has struck the earth.
Thunderbolts are collected with enthusiasm and then kept at home, for it is believed that a thunder-arrow protects a house from lightning. People especially like to keep them in their milk rooms.
Stomach-aches can be cured by scraping off and swallowing a little of the thunderbolt.
The toadstone, a fossilized sea-urchin, is also considered to be a proven protective agent against lightning, and is therefore kept at home, especially in milk rooms.
The farmers of Rügen often place in their swine troughs the ball-shaped stone kernels of the sea-urchin (ananchytes ovatus) that are often found in chalk. These presumably aid in the fattening of the swine and also protect the animals from red murrain.
Toadstones are also called "cross-stones" or "star-stones," the latter name coming from the belief that they fall from heaven or from the stars.
Cross-stones are placed in the milk room to protect the milk from "getting something." However, if the milk has already been bewitched, then the stones are placed in a milk sieve.