Question: What are some characteristics of tourmaline?
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In late 1989 a team led by gemstone prospector Heitor Dimas Barbosa uncovered in a small mountain range what some consider to be the finest tourmaline crystals ever found.
A trace of copper gives the tourmalines a vivid turquoise color that had never been seen before in the gems, and is sometimes referred to as "neon".
The "neon" paraiba tourmaline, a vivid blue and blue green, has also been found in other deposits close to the Batalha mine of Barbosa, and also in the neighboring state of Rio Grande do Norte.
The bright colors of this tourmaline are due to the presence of copper.
Around 2000, a similar copper-containing tourmaline was found in Nigeria, although the colors are not as intense.
Around 2005, beautiful crystals of copper-containing tourmaline were found in Mozambique.
Initially, the nomenclature for this tourmaline was "Paraíba tourmaline".
Note the capitalization and the accent on the "i".
In 2006, the LMHC (Laboratory Manual Harmonization Committee) agreed that "paraiba" should refer to a variety of tourmaline, and not indicate a geographic origin.
Note "paraiba" is not capitalized, and does not have an accent on the "i".
For more information on paraiba tourmaline, see article on tourmaline.
The term "paraiba tourmaline" may now refer to gems found in Brazil, Nigeria, and Mozambique that contain copper and have the characteristic blue-green color. 
Some fine gems and specimen material has been produced in the United States, with the first discoveries in 1822, in the state of Maine.
California became a large producer of tourmaline in the early 1900s.
The Maine deposits tend to produce crystals in raspberry pink-red as well as minty greens.
The California deposits are known for bright pinks, as well as bicolors.
During the early 1900s, Maine and California were the world's largest producers of gem tourmalines.
The Empress Dowager Cixi of China loved pink tourmaline and bought large quantities for gemstones and carvings from the then new Himalaya Mine, located in San Diego County, California.
It is not clear when the first tourmaline was found in California.
Native Americans have used pink and green tourmaline as funeral gifts for centuries.
The first documented case was in 1890 when Charles Russel Orcutt found pink tourmaline at what later became the Stewart Mine at Pala, San Diego County. 
Opaque black schorl and yellow tsilaisite are idiochromatic tourmaline species that have high magnetic susceptibilities due to high concentrations of iron and manganese respectively.
Most gem-quality tourmalines are of the elbaite species.
Elbaite tourmalines are allochromatic, deriving most of their color and magnetic susceptibility from schorl (which imparts iron) and tsilaisite (which imparts manganese).
Red and pink tourmalines have the lowest magnetic susceptibilities among the elbaites, while tourmalines with bright yellow, green and blue colors are the most magnetic elbaites.
Dravite species such as green chromium dravite and brown dravite are diamagnetic.
A handheld neodymium magnet can be used to identify or separate some types of tourmaline gems from others.
For example, blue indicolite tourmaline is the only blue gemstone of any kind that will show a drag response when a neodymium magnet is applied.
Any blue tourmaline that is diamagnetic can be identified as paraiba tourmaline colored by copper in contrast to magnetic blue tourmaline colored by iron. 
Tourmaline has a variety of colors.
Usually, iron-rich tourmalines are black to bluish-black to deep brown, while magnesium-rich varieties are brown to yellow, and lithium-rich tourmalines are almost any color: blue, green, red, yellow, pink, etc.
Rarely, it is colorless.
Bi-colored and multicolored crystals are common, reflecting variations of fluid chemistry during crystallization.
Crystals may be green at one end and pink at the other, or green on the outside and pink inside; this type is called watermelon tourmaline.
Some forms of tourmaline are dichroic, in that they change color when viewed from different directions.
The pink color of tourmalines from many fields is the result of prolonged natural irradiation.
During their growth, these tourmaline crystals incorporated Mn2+ and were initially very pale.
Due to natural gamma ray exposure from radioactive decay of 40K in their granitic environment, gradual formation of Mn3+ ions occurs, which is responsible for the deepening of the pink to red color. 
Almost every color of tourmaline can be found in Brazil, especially in the Brazilian states of Minas Gerais and Bahia.
In 1989, miners discovered a unique and brightly colored variety of tourmaline in the state of Paraíba.
The new type of tourmaline, which soon became known as paraiba tourmaline, came in blue and green.
Brazilian paraiba tourmaline usually contains abundant inclusions.
Much of the paraiba tourmaline from Brazil actually comes from the neighboring state of Rio Grande do Norte.
Material from Rio Grande do Norte is often somewhat less intense in color, but many fine gems are found there.
It was determined that the element copper was important in the coloration of the stone.