earth science

Hokutolite

Hokutolite is a earth science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Hokutolite rather than just read about it. In short: Hokutolite is the only mineral variety named after a Taiwanese place (Hokuto is the Japanese name for Beitou). Hokutolite is a rare mineral containing radioactive radium elements generated by the hot spring environment, and is currently found only in Beitou Hot Spring in Taipei City, and Tamagawa Hot Spring in Akita Prefecture, Japan.

Key takeaways

Hokutolite belongs to earth science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Hokutolite to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Hokutolite from memory before moving on to harder problems.

Reference excerpt

Hokutolite is the only mineral variety named after a Taiwanese place (Hokuto is the Japanese name for Beitou). Hokutolite is a rare mineral containing radioactive radium elements generated by the hot spring environment, and is currently found only in Beitou Hot Spring in Taipei City, and Tamagawa Hot Spring in Akita Prefecture, Japan. In Japan, the Ministry of Education, Culture, Sports, Science, and Technology has designated it as a "Special Natural Monument". In Taiwan, it is designated as a Natural Cultural Landscape, and the Taipei City Government has designated a natural reserve in the Beitou River upstream of the Beitou Hot Spring Museum.

Characteristics Hokutolite is a variety of baryte, a sulfate mineral of the orthorhombic system. The chemical composition of Hokutolite varies greatly, especially when it has a structure of light and dark interphase rings, and the molecular formula of the chemical composition calculated for different rings is between (Pb0.35-Ba0.65)SO4 and (Pb0.20-Ba0.80)SO4. The highest BaO content of Hokutolite is about 42% and the lowest is 32%. The BaO content of pure baryte (BaSO4) should be 65.7%. The molecule ratio of PbSO4 to BaSO4 can range from 21:79 to 32:68 (its average value is close to 27:73). Therefore, the content of lead and barium is not fixed, but changes in the range of 1:4 to 1:2 (lead:barium), with the content of barium greater than lead. Hokutolite is also radioactive because it contains radium.

History In 1905 (Meiji 38), Okamoto Yohachiro, who was a technician in the Mining Division of the Bureau of Productive Industries of the Government-General of Taiwan and a displayer at the Museum attached to the Department of Mines and Industry of the Government-General of Taiwan (now the National Taiwan Museum), first discovered sediment in the Beitou River near Beitou's Long Nice Hot Spring, but did not study it in depth at that time. In 1907 (Meiji 40), Okamoto found mineral crystals of Hokutolite, and after preliminary tests, it was found to have a high density and to contain lead (Pb), which was produced in an acidic hot spring environment, so it was temporarily called anglesite (PbSO4), a commonly known mineral. Later, Okamoto placed the mineral crystals on an unexposed glass negative in a laboratory darkroom, and after 10 days of development, the negative was found to be completely light-sensitive, confirming the presence of radioactive elements in the mineral crystals. In the same year, Professor Kotora Jimbo of Tokyo Imperial University discovered this mineral specimen, which is the same as the specimen collected by Hirosaburo Sakurai at Tamagawa Hot Spring in 1898 in the Mineral Specimen Room of Tokyo Imperial University. In 1912 (Taisho 1), Professor Kotora Jimbo brought the specimens of minerals collected by Okamoto in Beitou to the International Mineral Conference in St. Petersburg, the capital of Russia, and submitted an application for the examination of new mineral species discovery. Together with Professor Vernardsky, the Chairperson of the Russian Committee for Radium Mining Investigation, Professor Kotora Jimbo jointly named the newly discovered mineral Hokutolite (Hokuto is the Japanese name for Beitou, and -lite is a suffix given to rocks and minerals in English). The government also immediately enacted a mining ban along Beitou River. On April 25, 1923 (Taisho 12), the Crown Prince Hirohito visited Beitou and surveyed the Beitou River, and later set up a memorial monument (currently located in the vicinity of the Long Nice Hot Spring) to commemorate this event.

Related research In 1915, the Bureau of Productive Industries of the Government-General of Taiwan published the Hokutolite Survey Report, which introduced the distribution area of Hokutolite, mineralogical research data, and its radiological phenomena. In 1928, the eleventh list of new mineral names was published (Spexcer, L. J. et al., Eleventh list of new mineral names), stating that one of the minerals in the British Museum was named lead barite, a variant of anglesite with a chemical composition of 5PbSO4．BaSO4, discovered by mineralogist Kolbeck in 1907, is of Chilean origin, named after Professor Julius Albin Weisbach of Germany, and is the same mineral as Hokutolite. Due to the lack of radiation sources, a component of Hokutolite, polonium (Po), was often used as a reference material for atomic nucleus experiments during the Japanese colonial rule, making Hokutolite of great significance in the history of physics in Taiwan. On the evening of July 25, 1934 (Showa 9), the team of Bunsaku Arakatsu of the Physics Chair of the Taipei Imperial University successfully completed an artificial impact experiment on atomic nuclei. This was the first successful experiment in Asia and the second in the world. One of the key factors in the success of the lead was the use of the polonium from Hokutolite as a comparative value. In 1961, the former director of the Academia Sinica of the Republic of China, Yuan-Tseh Lee, wrote his master's thesis on "A Study of the Radioactivity of Beitou Stone" when he was a student at National Tsing Hua University, also with Hokutolite as a research topic. In 1995, Lian-Sheng Tzeng found that the natural radioactive nuclei of Hokutolite contained 2.256×10−9 grams of radium-226 and 4.87×10−13 grams of radium-228.

Protection and rehabilitation

On November 26, 1933 (Showa 8), the Government-General Taiwan designated Hokutolite as a Natural Monument in accordance with the Law for the Preservation of Historic and Natural Monuments. In 1952 (Showa 27), the Ministry of Education designated it as a Special Natural Monument. In 2000, the Cultural Heritage Panel of the Executive Yuan designated Hokutolite as a Natural Cultural Landscape and established the Beitou River (Hokutolite) Nature Reserve, which was the first mineral in Taiwan to be included in the preservation designation. On August 19, 2011, Beitou Hot Spring and Tamagawa Hot Spring became sister hot springs. On December 26, 2013, the Taipei City Government established the Hokutolite Natural Reserve, the first instance in Taiwan where a local government set up a natural reserve to protect a mineral ore.

References

Illustrations

Worked examples

Example 1 — a first encounter with Hokutolite

Start with the simplest possible case. Write down what Hokutolite claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Hokutolite before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Hokutolite ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Hokutolite

In research: Hokutolite appears in earth science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Hokutolite in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Hokutolite is common in secondary-school and first-year university syllabi. It links to neighbouring topics Barium minerals, Geology of Taiwan, Lead minerals, so understanding it makes those chapters shorter.
In everyday life: Look for Hokutolite outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Hokutolite in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Hokutolite means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Hokutolite out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Hokutolite in simple terms?

Why does Hokutolite matter?

Because it connects several earth science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Hokutolite?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Hokutolite.