The "thunderstone" is usually "a beautifully polished, wedge-shaped piece of greenstone," says a writer in the Cornhill Magazine, 50-517. It isn't: it's likely to be of almost any kind of stone, but we call attention to the skill with which some of them have been made. Of course this writer says it's all superstition. Otherwise he'd be one of us crude and simple sons of the soil.
Conventional damnation is that stone implements, already on the ground—"on the ground in the first place"—are found near where lightning was seen to strike: that are supposed by astonished rustics, or by intelligence of a low order, to have fallen in or with lightning.
Throughout this book, we class a great deal of science with bad fiction. When is fiction bad, cheap, low? If coincidence is overworked. That's one way of deciding. But with single writers coincidence seldom is overworked: we find the excess in the subject at large. Such a writer as the one of the Cornhill Magazine tells us vaguely of beliefs of peasants: there is no massing of instance after instance after instance. Here ours will be the method of mass-formation.
Conceivably lightning may strike the ground near where there was a wedge-shaped object in the first place: again and again and again: lightning striking ground near wedge-shaped object in China; lightning striking ground near wedge-shaped object in Scotland; lightning striking ground near wedge-shaped object in Central Africa: coincidence in France; coincidence in Java; coincidence in South America—
We grant a great deal but note a tendency to restlessness. Nevertheless this is the psycho-tropism of science to all "thunderstones" said to have fallen luminously.
As to greenstone, it is in the island of Jamaica, where the notion is general that axes of a hard greenstone fall from the sky—"during the rains." (Jour. Inst. Jamaica, 2-4.) Some other time we shall inquire into this localization of objects of a specific material. "They are of a stone nowhere else to be found in Jamaica." (Notes and Queries, 2-8-24.)
In my own tendency to exclude, or in the attitude of one peasant or savage who thinks he is not to be classed with other peasants or savages, I am not very much impressed with what natives think. It would be hard to tell why. If the word of a Lord Kelvin carries no more weight, upon scientific subjects, than the word of a Sitting Bull, unless it be in agreement with conventional opinion—I think it must be because savages have bad table manners. However, my snobbishness, in this respect, loosens up somewhat before very widespread belief by savages and peasants. And the notion of "thunderstones" is as wide as geography itself.
The natives of Burma, China, Japan, according to Blinkenberg (Thunder Weapons, p. 100)—not, of course, that Blinkenberg accepts one word of it—think that carved stone objects have fallen from the sky, because they think they have seen such objects fall from the sky. Such objects are called "thunderbolts" in these countries. They are called "thunderstones" in Moravia, Holland, Belgium, France, Cambodia, Sumatra, and Siberia. They're called "storm stones" in Lausitz; "sky arrows" in Slavonia; "thunder axes" in England and Scotland; "lightning stones" in Spain and Portugal; "sky axes" in Greece; "lightning flashes" in Brazil; "thunder teeth" in Amboina.
The belief is as widespread as is belief in ghosts and witches, which only the superstitious deny today.
As to beliefs by North American Indians, Tyler gives a list of references (Primitive Culture, 2-237). As to South American Indians—"Certain stone hatchets are said to have fallen from the heavens." (Jour. Amer. Folk Lore, 17-203.)