2 Nisan 2013 Salı

Rhode Island State Mineral

Rhode Island State Mineral


Bowenite is a compact and dense variety of antigorite or chrysotile, which are common members of the serpentine group. Bowenite is a synonym of tangawaite. Bowenite is closely related to jade and occurs in similar translucent shades of forest green, olive green, and yellowish green, as well as in blue, blue-green, white, gray, brown, and other shades of yellow. Bowenite has a waxy luster. It is a hydrous silicate of magnesium, sometimes containing iron, with little or no aluminum.
Rhode Island geologist George T. Bowen discovered this mineral in the early 19th century. Bowen first described the mineral from an occurrence at Dexter Quarry in Lincoln, Rhode Island in 1822. The mineral was later named in Bowen’s honor, and on May 26, 1966, was adopted as the official state mineral of Rhode Island. This same resolution also designated cumberlandite Rhode Island’s official rock.
This mineral was named for the geologist who first discovered it, George T. Bowen.
Rhode Island’s state mineral occurs as densely packed fibers in masses. It forms minute crystals. Bowenite commonly replaces ultramafic rocks and siliceous dolostone. This mineral forms in association with chromite, magnetite, chrysotile, and olivine. In Rhode Island, bowenite forms in several areas in the northern part of the state in association with limestone.
This mineral occurs in the northeastern United States, as well as in a handful of other countries throughout the world.
  • United States: Maine, Massachusetts, New York, Pennsylvania, Rhode Island, and Vermont
  • Afghanistan
  • China
  • New Zealand
  • South Africa
Bowenite is useful to lapidarists, mineral collectors, and gemologists, as it takes a fine polish if tumbled. It can be faceted and carved into cabochons for use as a gemstone. It is also carved into decorative sculptures. The Mâori in New Zealand have used bowenite, along with jade, for weapons, tools, ornaments, and jewelry. However, because bowenite is relatively low in demand and does not command high prices, it is normally considered uneconomical to mine.
Those subscribing to mineral and crystal therapy believe bowenite can aid in treating and curing diseases of the heart and blood, as well as helping one with personal issues of the heart.
The largest known bowenite specimen resides in the National Museum of China. It is a carving approximately 14 inches (35.6 cm) in size.
A famous Buddha statue, known as the Onassis Buddha, fetched £1.3 million ($2.5 million) at a Christie’s auction in London on June 11, 2008. The statue is made of bowenite and adorned with rubies and diamonds. Formerly owned by Aristotle Onassis and kept on the yacht he named for his daughter Christina, the statue was purchased by Moscow collector Alexander Ivanov. The Buddha, made by Fabergé circa 1900, had been expected to fetch only £250,000 to £350,000 (approximately $407,000 to $570,000), according to Christie’s.
Bowenite has been used as a substitute for nephrite jade, since the two are quite similar in appearance. In fact, the only way to distinguish between the two stones is by testing the specific gravity and density.
State Mineral
Bowenite Specimen
State Mineral
Sliced Bowenite Showing Grain and Texture
State Mineral
Bowenite Jewelry
State Mineral
Bowenite Pendant
Group: Kaolinite-serpentine
Chemical Formula: Mg3Si2O5(OH)4
Crystal Structure: Monoclinic
Hardness (Mohs): 5-6 
Color: Green
Transparency: Opaque to translucent
Luster: Vitreous, greasy
Density: 2.5 - 2.6, Average = 2.54
Streak: Greenish white
Cleavage: Good
Fracture: Brittle 
Tenacity: Brittle
Some data courtesy of the Mineralogical Society of America
Author: World Trade Press

Hiç yorum yok:

Yorum Gönder