Hokutolite is the only mineral named after a
Taiwan
Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the nort ...
ese place (Hokuto is the Japanese name for
Beitou
Beitou District is the northernmost of the twelve districts of Taipei City, Taiwan. The historical spelling of the district is Peitou. The name originates from the Ketagalan word ''Kipatauw'', meaning witch. Beitou is the most mountainous and ...
) among the more than 4,000 naturally occurring minerals in the world. 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
is a hot spring located in the city of Semboku, Akita in northern Japan.
Water profile
The spring has a flow of 9000 liters/minute and feeds a 3-meter wide stream with a temperature of 98 °C. The water from Tamagawa Hot Spring is extrem ...
in Akita Prefecture, Japan. In Japan, the
has designated it as a "
Special Natural Monument". In Taiwan, it is designated as a "Natural Cultural Landscape", and the
Taipei City Government
The Taipei City Government (TCG) is the municipal government of Taipei.
History
The Taihoku City Government was founded on 10 October 1920 in Taihoku Prefecture during Japanese colonial rule. The original city hall was located at the site of ...
has designated a natural reserve in the Beitou River upstream of the
Beitou Hot Spring Museum
The Beitou Hot Spring Museum () is a museum about hot spring in Beitou Park, Beitou District, Taipei, Taiwan.
History
The construction of the building started in 1911 and completed in 1913 during the Japanese rule of Taiwan. It was init ...
.
Characteristics
Hokutolite is a subspecies of barite, a
sulfate mineral
The sulfate minerals are a class of minerals that include the sulfate ion () within their structure. The sulfate minerals occur commonly in primary evaporite depositional environments, as gangue minerals in hydrothermal veins and as secondary mine ...
of the
orthorhombic system
In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with a r ...
. 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 (Pb.35-Ba.65)SO
4 and (Pb.20-Ba.80)SO
4. The highest BaO content of Hokutolite is about 42% and the lowest is 32%. The BaO content of pure barite (BaSO
4) should be 65.7%. The molecule ratio of PbSO
4 to BaSO
4 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 the alkaline earth metal element – radium.
History
In 1905 (
Meiji 38), Mr.
Okamoto Yohachiro, who was a technician in the Mining Division of the Bureau of Productive Industries of the
Government-General of Taiwan
The Government-General of Taiwan (Japanese: , Kyūjitai: , Hepburn: ''Taiwan Sōtoku-fu''; ; Tâi-lô: Tâi-uân Tsóng-tok-hú; Pha̍k-fa-sṳ=Thòi-vân Chúng-tuk-fú) was the government that governed Taiwan under Japanese rule between 189 ...
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
The National Taiwan Museum (NTM; ), established in 1908, is the oldest museum in the Republic of China (Taiwan). It was founded by the colonial government during Taiwan's period of Japanese rule. The museum is located in Zhongzheng District, Tai ...
), 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 specific gravity and to contain lead (Pb), which was produced in an acidic hot spring environment, so it was temporarily called "anglesite" (PbSO
4), 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 Mr. 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 means rock and mineral in English).
The government also immediately enacted a mining ban along Beitou River.
[臺北市政府觀光傳播局,《女巫嬉遊記 發現北投の湯與美》,臺北市:臺北市政府觀光傳播局,2012]
On April 25, 1923 (Taisho 12), the Crown Prince
Hirohito
Emperor , commonly known in English-speaking countries by his personal name , was the 124th emperor of Japan, ruling from 25 December 1926 until his death in 1989. Hirohito and his wife, Empress Kōjun, had two sons and five daughters; he was ...
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
The British Museum is a public museum dedicated to human history, art and culture located in the Bloomsbury area of London. Its permanent collection of eight million works is among the largest and most comprehensive in existence. It docum ...
was named lead barite, a variant of anglesite with a chemical composition of 5PbSO
4.BaSO
4, 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, the composition of Hokutolite,
Polonium
Polonium is a chemical element with the symbol Po and atomic number 84. Polonium is a chalcogen. A rare and highly radioactive metal with no stable isotopes, polonium is chemically similar to selenium and tellurium, though its metallic character ...
(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
was a Japanese physics professor in the World War II Japanese Atomic Energy Research Program of the Imperial Japanese Navy. Arakatsu was a former student of Albert Einstein.
Career
In 1928, Arakatsu became a professor in Taihoku Imperial Uni ...
of the Physics Chair of the
Taipei Imperial University successfully completed an artificial impact experiment on
atomic nuclei
The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment. After the discovery of the neutron ...
. 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
Academia Sinica (AS, la, 1=Academia Sinica, 3=Chinese Academy; ), headquartered in Nangang, Taipei, is the national academy of Taiwan. Founded in Nanking, the academy supports research activities in a wide variety of disciplines, ranging from ...
of the Republic of China,
Yuan-Tseh Lee
Yuan Tseh Lee (; born 19 November 1936) is a Taiwanese chemist and a Professor Emeritus at the University of California, Berkeley. He was the first Taiwanese Nobel Prize laureate who, along with the Hungarian-Canadian John C. Polanyi and America ...
, wrote his master's thesis on "A Study of the Radioactivity of Beitou Stone" when he was a student at
National Tsing Hua University
National Tsing Hua University (NTHU; ) is a public research university in Hsinchu City, Taiwan.
National Tsing Hua University was first founded in Beijing. After the Chinese Civil War, the then-president of the university, Mei Yiqi, and other ...
, also with Hokutolite as a research topic.
In 1995, Lian-Sheng Tzeng found that the natural radioactive nuclei of Hokutolite contained 2.256*10E-9 grams of radium-226 and 4.87*10E-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
The Executive Yuan () is the executive branch of the government of the Republic of China (Taiwan). Its leader is the Premier, who is appointed by the President of the Republic of China, and requires confirmation by the Legislative 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
{{Reflist, 30em
Barium minerals
Lead minerals
Sulfate minerals
Geology of Taiwan