One of three naturally occurring isomorphic forms of titanium dioxide: anatase, rutile, and brookite. Rutile forms a hard, reddish brown crystal with a metallic luster. Small amounts of natural rutile may have been used as a pale yellow to brown pigment. Synthetic rutile is produced both as a gemstone crystal and as a white powder for paint. Rutile gemstone crystals prepared by the Verneuil process are used as imitation diamonds in paste jewelry. The anatase form of titanium dioxide was a common white pigment in the early 20th century. Once the first commercially viable method for producing rutile was developed in 1938, production shifted to rutile because white paints with anatase pigments were subject to chalking and yellowing As a pigment, rutile has good opacity, a high refractive index and is nontoxic. It is the most important white pigment in the commercial paint industry even though its color tends to be slightly yellow.
Synonyms and Related Terms
titanium dioxide; synthetic rutile; imitation diamond; rutile (Eng., Fr.); rutilo (It., Esp., Port.); rutil (Nor., Sven.); ; Titanweiss (Rutil) (Deut.); leyko toy titanioy (Roytilio) (Gr.); bianco di titanio (rutilo) (It.); titaandioxide (rutiel) (Ned.); rútilo (Port.)
Insoluble in acids. Tetragonal crystal system with prismatic habit (often twinned). Crystals may appear red in transparent light. Particle size 0.2 - 0.5 micrometers
High birefringence and interference colors Fluoresces gray or dark purple
|Mohs Hardness||6.0 - 6.5|
|Refractive Index||2.71 - 2.72|
Hazards and Safety
Nontoxic. No significant hazards.
° M.Laver, "Titanium Dioxide Whites", Artists Pigments, Volume 3, E. West FitzHugh (ed.), Oxford University Press: Oxford, 1997. ° Mineralogy Database: Rutile° Walter C. McCrone, "Polarized Light Microscopy in Conservation: A Personal Perspective" JAIC 33(2):101-14, 1994. (contains a table of dates on the history of titanium white as a pigment)
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