Taiwan Rose Stone

Taiwan Rose Stone is a combination of minerals, mainly rhodonite, rhodochrosite, manganese oxide, calcite, dolomite and quartz. Taiwan Rose Stone is produced in Hualien's Sanzhan River, Mugua River, Liwu River, Heping River and Ximao Mountain in Dong'ao, Yilan, as well as other areas in Taiwan. The name “Taiwan Rose Stone” is a colloquial term rather than a universally recognized nomenclature.
==Origins of the name==
There are two narratives as to the origins of the name “Taiwan Rose Stone”. The first suggests that the pink hue resembling a rose emerges when manganese-bearing rocks are cut and polished. The second revolves around the practice in earlier processing workshops, where the manganese-bearing rocks were selectively carved, leaving behind the white and pink sections, which were subsequently marketed in the form of roses.
Taiwan Rose Stone was earlier known as Rhodonite, but scholars found that Taiwan Rose Stone is composed of a variety of different manganese-bearing minerals, of which rhodonite is only one, and some Taiwan Rose Stone contain no rhodonite at all, so an unprocessed piece of Taiwan Rose Stone can be called “manganese-rich rock” or “Rhodonite rock”.
==Discovery==
The first official scholarly study of Taiwan Rose Stone was published in academic journals in 1912. The Japanese mineralogist Okamoto Yohachiro published in the Transactions of the Natural History Society of Taiwan, “The Rhodonite and the Clinoclase, Newly Discovered”, in which it was mentioned that peach-red rhodonite was first found in eastern Taiwan in that year.
In 1932, Hattori Takehiko and Kono Takeji published “Rhodonite From Too, Suo-Gun, Taihoku Province” in the Taiwan Tigaku Kizi, which was the first paper on the chemical analysis of rhodonite in Taiwan.
==Mineral composition==
Taiwan Rose Stone is composed of a variety of minerals, mainly rhodonite, rhodochrosite, and pyroxmangite; pyrolusite, psilomelane, hausmannite, and inesite; interspersed with brownish-yellow and grayish-white quartz, kutnohorite, and ankerite; and trace amounts of orthoclase, chlorite, spessartine, muscovite, epidote, calcite, tephroite, hexagonite,celsian, actinolite, braunite, pyrite, albite, magnetite, and asbestos.
==Geogenesis==
The manganese in rose stones originates from seafloor manganese nodules, which are metallic clumps of sediment in the seabed, consisting mainly of hydrated oxides of iron and manganese, sometimes containing large amounts of transition metals (e.g., cobalt, nickel, copper, etc.) and other rare metals, which can be divided into three main groups depending on their source:
# Hydrothermal action: The hot water solution formed by the volcanic activity under the sea mixes with seawater to produce the precipitation of metallic elements.
# Hydrogenesis: The dissolved substances in seawater precipitate out due to oversaturation, resulting in the precipitation and enrichment of metal elements.
# Diagenesis: The metal elements in the sediment migrate to the junction of seawater and marine crustal sediment, producing an enrichment phenomenon. 
The submarine manganese nodules were uplifted by plate movements, accompanied by lithification and metamorphism of marine sediments and marine crustal materials, resulting in the formation of metamorphic rocks such as rose stone, meta-chert, marble and green rocks. The earth's crust continues to rise and the rocks are exposed by weathering and erosion.
==Occurrence and Distribution==
Taiwan Rose Stone is produced in the Changchun Formation of the Tananao Schist on the eastern side of the Central Mountain Range in Taiwan, which is the oldest stratum in Taiwan with a stratigraphic age of 300 to 100 million years. The lithologies of the Changchun Formation are mainly green schist, metabasite, quartz schist, a few chloritoid rocks, and Taiwan Rose Stone (manganese-rich rocks), which occurs in a lenticular or vesicular form.
There are two types of Taiwan Rose Stones: outcrops and tumbled stones. The outcrops are mainly located in mountainous areas, such as Sanzhan River, Heping River, the upper reaches of Mugua River, Lushui and Luoshao in Liwu River, the Central Mountain Range near Ruisui, Tianxiang in the Central Cross-Island Highway, Wenshan Hot Springs, Jiabeili Mountain in the north of the Jinma Tunnel, and Ximao Mountain in Dong'ao. The tumbled rocks are found in the downstream rivers of the above-mentioned outcrops, where rocks crumble from the outcrops to the rivers through weathering and erosion, and are transported to the downstream riverbeds by the water flow, resulting in a rounded appearance after a long time of washing and friction. Tumbled Taiwan Rose Stones are often found in Sanzhan River, earning it the moniker “Rose River”.
==Quarrying==
In 1931, Ogasawara Mitsuo, a technician in the Mineral Division of the Japanese Government-General’s Office, discovered the distribution of manganese-rich rocks near Dong'ao, and the following year discovered the Ximao Mountain deposit. However, it was not considered economically viable due to the low grade of most of the manganese-bearing rocks and the limits of manganese refining technology at the time, whereby it was deemed uneconomical to quarry and process.
In 1976, a proposal was submitted for manganese extraction in the eastern region of Liwu Mountain in Hualien. However, owing to the area's remote location, no mining activities were carried out, and the project was ultimately abandoned following the establishment of Taroko National Park.
In the 1980s, Taiwan Rose Stones were processed into attractive ornamental stones for sale and collection, which became a trend in the lapidary community. Initially, there was plenty of supply, but as more and more people started collecting the stone, the supply of raw stones were quickly depleted. Occasionally, the tumbled rocks can only be found in the lower stretches of rivers after typhoons, or alternatively, one must venture underwater and delve into the estuary to salvage them. The only way to see the Taiwan Rose Rock outcrops is in the National Park Control Area. 
==Processing and value==
Before the 1980s, Taiwan Rose Stone was considered a manganese ore with no economic value, but after processing and polishing it became an ornamental stone with collector's value. Prior to processing, Taiwan Rose Stone exhibits a black hue attributable to surface manganese oxidation, necessitating the removal of the weathered layer to unveil the stone's authentic coloration.The pink rhodonite, black manganese-bearing minerals and other colored minerals form an ink painting-like imagery, giving rose stone its name of “painting in stone, stone in painting”.
There are two main ways to process Taiwan Rose Stone: grinding the original stone and slicing it. Grinding the original stone retains its original shape, removing only the black outer shell, polishing it and then applying glossy lacquer to preserve its vivid color; slicing the original stone is sawn into pieces, which can be framed or made into a wooden table for placement.
The price of an ornamental Taiwan Rose Stone depends on the color, luster, crystallinity, texture, size and origin of the stone. In the early days, the market price was about NT$100-300 per kilogram. However, due to excessive mining depleting its availability, the price rose to more than NT$1,000 per kilogram; nowadays, the price is not based on “kilogram” but on “pieces”, ranging from several thousand to several hundred thousand dollars each, with rare and precious items even fetching several million dollars.
Category:Stones
Category:Rhodonite
Category:Rhodochrosite
Category:Calcite
Category:Dolomites
Category:Quartz