Photo of Rubellite Tourmaline in Processed & Rough Form
Rubellite Tourmaline is a mineral with a hardness of 8 out of 10 on the Mohs scale of mineral hardness [?]. These Trigonally structured gems are made of complex borosilicate, their full chemical compound being Na(Li,Al)3Al6(BO3)3Si6O18(OH)4.
Rubellite is the pink to red variety of Tourmaline, which is a complex borosilicate of aluminum and alkali, with iron, magnesium, and other cations.
It is found as fine acicular crystals in rocks, or as large individual crystals grown upon matrix where they may reach a weight of several kilograms. Most form elongated and striated trigonal (three-sided) prisms and these are terminated with trigonal pyramid faces. Tourmaline crystals show a polar morphological development, which means that in complete crystals (doubly terminated), the upper and lower pyramidal forms are different.
The color of rubellite varies from pink of varying degrees of intensity to a red which is quite attractive, although usually a bit lesslively than that of ruby; it may also be violet pink or red, and pink or red with a brownish tinge.
In many cases, the color is fairly distinctive: it is a bit subdued, and not enlivened by bright light like ruby. When the stone is cut with the table facet perpendicular to the axis of the prism, to achieve a deeper, redder color, it shows a strange loss of transparency. Pink tourmalines are, as a rule, also rather duller than other similar gems, but may be a beautiful, brilliant violet-pink.
Tourmalines are found in differentiated dikes of silica-ruch intrusive rocks and is quite common around granite, where pegmatitic, pneumatolytic mineralizations are abundant.
Rubellite is found in Siberia (some even call the violet-red variety "siberite"), Burma, Sri Lanka, Brazil, the USA, and Madagascar.
Other names of rubellite include:
Elbaite - a pale red, borosilicate mineral of tourmaline group from Elba, Italy.
Nerchinsk rubellite - a pink variety of tourmaline or rubellite from Nerchinsk, Siberia, Russia.
Misleading terms include:
Red schorl - a misleading term for rubellite tourmaline.
Siberian ruby - a misleading term for rubellite a red variety of tourmaline from Siberia, Russia.
San Diego ruby - a misleading term for rubellite a red variety of tourmaline from San Diego, California (USA).
Rubellite is sometimes mistaken for reddish-brown topaz which turns pink when heat-treated .
The specific gravity [?] for Rubellite Tourmaline is 3.06, its refractive index [?] is 1.62-1.64, and its double refraction [?] is 0.018.
History
Tourmaline derives its name from the Sinhalese word "turamali", referring to gems of unknown identity-probably zircons.
Due to its rich and varied colors, tourmaline was already a popular stone in Victorian times, and has remained popular to the present. Its colors sometimes gave rise to confusion. The large "ruby" that King Gustav III of Sweden gave to Catherine the Great of Russia in 1786, was in fact a rubellite.
Industrial Usages
Like all tourmalines, rubellite has strong pleochroism, sometimes visible as a deeper color or lesser transparency along the aixs of the prism. It is cut into all shapes; cabochons when the stone is too full of inclusions, but more often faceted oval, round, pear-shaped or other creative styles. Quite large stones are often seen. When cut as faceted gemstones, some specimens show excellent cat's-eye effects.
The liveliest, bright red or very attractive pink gems with few inclusions are not common and are quite valuable secondary gems. Stones of more subdued color are readily available and quite modestly priced. It is neither imitated nor produced synthetically.
A distinctive physical property of all tourmalines is pyroelectricity. Through warming or rubbing the crystal, an electric charge is produced, one end positive and the other negative. They also exhibit piezoelectric properties so that they have important application as a frequency stabilizer.
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