Should every creek have its own mission to breed the life of a certain species? 

Compared to the truth-  the breeding of Sakura Salmon (櫻花鉤吻鮭) is the mission of Qijiawan Creek (七家灣溪), what mission of Beitou creek will be?  We could say the breeding of Hokutolite would be the mission of Beitou creek offered by the God.

Walking up along the Beitou park from its entrance, you will immediately find Beitou creek meandering around Beitou Park.  Long before 100 years, during the Japanese colonial period,  a technician, Okamoto Yohachiro, who worked for “Minerals Division” of Taiwanese Government house (臺灣總督府), found a stone with radiation in Beitou creek- the finding was attributed to the exposure of negatives in camera which he put on some rocks.  It was proved a new mineral with radiation in year 1909. Later, in year 1912, this stone was named as Hokutolite – directly use the location's name where it was found. Hokuto is the Japanese pronunciation of Chinese characters(北投 ), and–lite means the stone ( or mineral ) scientifically. 

Few people understand there are only two places in this world created this kind of stone. One location is just situated in front of our living house- Beitou Creek. The depth of this small creek is lower than half meter; the river bank looks dirty whitening and even with sulfur smell- like the sour egg. Besides, there is no fish and shrimp for catching.  The first image of this small creek is not so lovable.

But some places  of this creek exposed with some stones and small waterfalls. And it was ever beautiful during the Japanese colonial period. Japanese at that time ever called these delicate waterfall as Otaki ''瀧.''

Hokutolite is originated starting from Geothermal Valley(地熱谷), where contains hot spring creek with rich mineral reserves. The original Andesite(安山岩) spread all over the creek bank, after whitening by creek water, the mineral elements were precipitated and crystallized  at the interface of Sulfonamide jarosite(磺鉀鐵礬).  It is the formation mechanism of Hokutolite.

According to the published research report about Hokutolite by Professor Mr. Pei-Yuan Chen ( Department of Geology of Taiwan University) in year 1963, at the river bank the grown up Hokutolite crystal at the crevice or at the bottom of dangling rock ( such as the cave under small waterfall) will be bigger in size.

The hokutolite at the river bank will be suffered with continuous friction by the water flow;

therefore some of them will be with smooth skin shell. And part of them will be washed off.

There are two types of the above mentioned Hokutolite; one type is hidden behind the small waterfall, it will be bigger in size. The other one type is similar as dumpling skin, it covered the external surface of the Andesite. Their special characteristics is they will expose the negative of taken photos once they are put closely. That was the reason why Okamoto san accidentally discovered Hokutolite is with radioactive feature. 

The generation of Hokutolite must be based on the natural, non polluted green hot spring.  Crystal precipitated bit by bit from the hot spring water after a long period. Then the generated crystal adhered on the stone of river bank. So it is scarce and precious.

It is said that Kokutolite is put in the hot spring pool at Tamagawa Hot Spring aiming to improve the health of

soakers via the minor radioactivity.

Though Hokutolite could be caused by the precipitation of hot spring, it won’t be immediately precipitated. The original temperature of Beitou and Tamagawa is higher than ninety degrees census.

When cooling down to the appropriate temperature, the precipitant will be adhered to the rock surface. However, only one millimeter thick deposit layer formed in more ten years.