Noun
A mineral usually of a reddish brown color, and brilliant metallic adamantine luster, occurring in tetragonal crystals. In composition it is titanium dioxide, like octahedrite and brookite.
Source: Webster's dictionaryAfter color follows clarity: similar to diamonds, a clear stone will command a premium, but a ruby without any needle-like rutile inclusions may indicate that the stone has been treated. Source: Internet
All natural rubies have imperfections in them, including color impurities and inclusions of rutile needles known as "silk". Source: Internet
Titanium Dioxide R715 by Hangzhou Epsilon Chemical is an alumina zirconia treated rutile pigment, produced by chloride process. Source: Internet
Improvements used include color alteration, improving transparency by dissolving rutile inclusions, healing of fractures (cracks) or even completely filling them. Source: Internet
In 2005 the Republic of Sierra Leone in West Africa had a production capacity of 23% of the world's annual rutile supply, which rose to approximately 30% in 2008. Source: Internet
In the latter case, the mineral no longer has a silicate structure, but that of rutile (TiO 2 ), and its associated group, which are simple oxides. Source: Internet