Fossa Magna Museum was added to Your Favorites!
Myōkō-Togakushi Renzan NP, Niigata
Claim this place to tell your story your way.
The museum’s outdoor Fossil Valley lets visitors search a 300-million-year-old reef. Finds include corals, crinoids, brachiopods, trilobites and goniatites—creatures from a long-vanished sea.
At the entrance, raw jade boulders evoke Itoigawa’s Jade Gorges—and the largest weighs 7 tonnes. It is a striking reminder that jade begins as massive, rough rock, not a polished gem.
About 700 Itoigawa jade specimens fill one gallery, with roughly 3,500 minerals displayed in another. The jade comes in white, lavender, blue and black as well as the familiar green.
Itoigawa jade formed roughly 520 million years ago, long before dinosaurs. In 2016, jade was selected as Japan’s national stone, so the museum’s specimens connect deep geological time with a modern national emblem.
Heinrich Edmund Naumann, the museum’s namesake, arrived from Germany at 20 and surveyed 10,000 km of Japan. He named the Fossa Magna—and the Naumann elephant was named in his honor, too.
The Fossa Magna is a broad, buried geological zone—not another name for the Itoigawa–Shizuoka Tectonic Line, which marks its western edge. Boreholes about 6 km deep still failed to reach the older basement below.
In the stone garden, a map of Japan marks the Fossa Magna, and raw jade forms the sundial’s hour marks. Nearby, water drops ring inside a hidden jar in a traditional sound feature called a suikinkutsu.
The museum’s story of Japan’s formation unfolds across two 200-inch screens—one on the wall and one on the floor—so the archipelago’s geological history plays out above and beneath visitors.
On designated days, museum curators identify small stones collected from places such as the beach—up to 5 per person. Timed tickets are limited, and when demand is high, they’re allocated by lottery.
In 2019, the museum invited people to submit amusing stones found in Itoigawa. About 400 entries arrived from around Japan—a cheerful reminder that even an ordinary pebble can catch people’s imagination.
When a local stream turned milky, trout died and rice plants withered, the city asked museum geologists to investigate. They traced the trouble to underground hot-spring water carrying white clay into the river.
The annual Sea of Japan Classic Car Review makes the museum an unlikely meeting place for motoring fans: around 200 classic cars gather from across Japan, followed by a parade through Itoigawa’s downtown.
Itoigawa was using the word “Geopark” for its local geological attractions in 1991, before the international geopark network existed. A museum curator applied the label to sites such as the Fossa Magna Park.
At nearby Chōjagahara, Jōmon residents worked jade into ornaments traded across Japan. The tough, hard-to-split stone also served as a hammer while they made stone axes, according to the archaeological site’s city guide.
Look for Nipponites in the fossil gallery: this ammonite’s famously strange shell coils in an irregular, tangled form rather than a neat spiral. It lived during the Cretaceous Period.
