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Aragonite

 

 

 

 

 

 

 Description
Aragonite is found only in basalt rock in a few places around the world, including Taiwan's Penghu islands, Sicily and the western U.S. Aragonite from Penghu is considered the most beautiful and has the richest colors. The main types are aragonite and calcite though some may also contain limonite, siderite, zeolite, chalcedony, agate or opal. White, yellow and brown are the most common colors with a shape similar to a cluster of grapes. Mineral hardness is 3 ~ 4 on the Mohs scale with a specific gravity of 3. Aragonite produced in Penghu varies in color and texture. Some form the "Aragonite Eye", a concentric circlular pattern, after polishing. 

Mineral Formation
Penghu's aragonite is formed in cavities within the basalt. During volcanic eruptions in the Miocene Epoch, gases in the lava expand as the pressure and temperature drops forming air holes in the basalt. Water then carries dissolved minerals into these spaces where they gradually accumulate over time. The crystals which form from the calcium, magnesium, iron and silicon deposits are known as "aragonite". 
 

Geographic Distribution
Fongguei and Shihli on Penghu proper, Houliao and Tongliang on Baisha Island, Hejie on Siyu, Siamen Islet, Chihsi, Waian, Wang-an Island, Jiangjyun-ao Islet and Dongji Islet.

Mining History
It is not known when Aragonite was first discovered in Penghu. Lu Ruo-teng composed the "Penghu Aragonite Song" during the Ming Dynasty while Jhou Yu-ren's "Ode to Aragonite" appears in A Brief History of the Penghu Prefectur (澎湖廳略志). Aragonite was therefore known and made use of by the late Ming or early Manchu Dynasty. Large-scale mining of aragonite in Penghu did not begin until the Japanese colonial period. High quality aragonite deposits were found by the Japanese Shida(志太) in Wang-an Township and Jiangjyun-ao. An aragonite processing factory was later set up in Wang-an Township in 1909. The aragonite industry reached its peak around the 1960's.

Steel hammers and chisels were used to dig aragonite out of the hard basalt. As it was difficult to keep the aragonite intact during mining, production was limited in scale and output. A century of mining meant high quality aragonite has become scarce. The increasing popularity of Penghu coral, the availability of new gemstones and rising environmental awareness has led to a gradual decline in the aragonite industry. The government now officially prohibits the mining of aragonite. 

Applications
Ornamental semi-precious stone, decorations and personal seals. 

Wenshih Academy
The Penghu Confucian Temple was originally the Wenshih Academy. Established in 1766 by Hu Jian-wei, Penghu's 18th local magistrate, it was the only public academy in Penghu during the Manchu Dynasty and also Penghu's earliest cultural venue.  The name Wenshih Academy ("Aragonite Academy") was chosen in the hopes that the academy would produce talent as diverse and colorful as locally-mined aragonite.

The Wenshih Academy was destroyed during the 1885 Sino-French War. It was rebuilt in 1895 under Japanese colonial rule. In a bid to preserve the local culture and exploit the Japanese reverence for Confucius, the Academy became the "Confucian Temple" we see today.

National Museum of Natural Science